Journal of medical ethics 1993; 19: 169-174

The great slippery-slope argument

J A Burgess University of Wollongong, New South Wales, Australia

Author's abstractWhenever some form of beneficent killing- for example,voluntary euthanasia - is advocated, the proposal isgreeted with a flood of slippery-slope arguments warningof the dangers of a Nazi-style slide into genocide. Thispaper is an attempt systematically to evaluatearguments of this kind. Although there are slippery-slopearguments that are sound and convincing, typicalformulations of the Nazi-invoking argument are foundto be seriously deficient both in logical rigour and in thesocial history and psychology required as a scholarlyunderpinning. As an antidote, an attempt is made bothto identify some of the likely causes ofgenocide and toisolate some of the more modest but legitimate fears thatlie behind slippery-slope arguments of this kind.

Whenever the question of the legalisation of volun-tary euthanasia is raised, the proposal is greeted witha flood of slippery-slope arguments. Here is a recentexample from William Reichel and Arthur J Dyck:

'If euthanasia were legalised, might we not thenregard certain individuals as unworthy of life? Such a

concept laid the foundation of the euthanasia move-

ment that began in Germany before the NationalSocialist movement and before Hitler's rise to power.This single idea of life devoid of value was influentialin the German medical profession's snowballinginvolvement with euthanasia. Before the Holocaust,physicians were the ones who selected patients andcarried out this practice. To those who say "it cannothappen here", we reply: imagine the easy marriagebetween respect for autonomy - for example, assist-ing the AIDS patient who requests euthanasia - andthe need for greater cost-containment - ie, thepatient's care is disproportionately expensive. Whatbegins for the patient's own wishes, may later beendorsed for economic reasons. If euthanasia were

legalised, individuals themselves might believe thatsociety does not want them to live' (1).

If this example is atypical, it is so only because it ismore detailed than is usual for arguments of thiskind (2). And one finds the argument, in some formor other, almost everywhere in applied ethics:indeed, a book has recently appeared by DavidLamb (3) which is structured entirely around theargument which appears there literally dozens oftimes.Many slippery-slope arguments in applied ethics

are simple in structure, highly specific in scope andmodest in the practical counsel they offer us. A goodexample involves the question whether to prescribedrug A or drug B to a patient. For the conditionconcerned, A might score best on almost all relevantcriteria whilst B does adequately on all, if less well onsome. Suppose, further, that there is no realisticpossibility of switching drugs in mid-treatment.Now, if A leads to tolerance, eventually needing tobe administered in a lethal dose, a simple and soundslippery-slope argument leads to the conclusion thatdrug B is to be preferred. But, Reichel, Dyck andLamb (4) - with many others - are not muchinterested in such modest and intuitively compellingarguments. They prefer to go for broke, offering the'One Great Slippery-slope Argument' (hereafter, theGreat Argument) as the only example of the genreworth writing about. The argument is simple inform: if we adopt such-and-such a particular changein our practices it just might start a slide into a moraldeterioration that ends with our committing Nazi-style atrocities. Clearly if such a charge were just -

and we have already seen that some slippery-slopearguments are good arguments - then this would bea very good reason not to adopt the change, at leastif the threat of deterioration were at all serious.Further, we know that such moral degeneration doesoccur - in Germany under the Nazis, as so oftenelsewhere, it did occur - so it is always a seriousquestion of great practical importance how suchdegeneration is caused.

Unfortunately, purveyors of the Great Argumentrarely if ever work it into a detailed slippery-slopeargument. They rest content with the sketchiest offormulations, leaving the detailed work to theiropponents: we've shown you (sketchily) that it mighthappen; now show us (in detail) that it couldn't. But

Key wordsSlippery slopes; euthanasia; genocide; cost-benefit analysis.

copyright. on F

ebruary 25, 2020 by guest. Protected by

http://jme.bm

j.com/

J Med E

thics: first published as 10.1136/jme.19.3.169 on 1 S

eptember 1993. D

ownloaded from

170 The great slippery-slope argument

this is a fraud. The mere presentation of a slope doesnothing to show that the onus of proof is on thereformer to demonstrate that a proposed change willnot lead to disaster. This mistake, although of no

great intellectual importance, sophistication or pro-fundity in itself, is nonetheless encountered oftenenough to deserve analysis and diagnosis and it isclearly of great practical importance, for many havebeen persuaded of its soundness. At the otherextreme we have those who regard any slippery-slopeargument as nothing more than a hollow rhetoricalflourish. No doubt, the prevalence of sketchy andimplausible examples - usually versions of the GreatArgument - has led many to this attitude, but we

have already seen that some modest slope argumentsare good arguments so the attitude must be aban-doned. Nevertheless, what we need is what non-

extremists have wanted all along: some sound and(preferably) non-technical practical advice in sortingthe good slippery-slope arguments from the bad.Here I shall concentrate only on the 'GreatArgument' and I shall attempt to show why it is a

bad argument.As a first step towards our objective, we should

note two reasons why the slippery-slope argumentpresented earlier as an example of a good argumentwas indeed good. First, it was modest: it showed howsome particular good could be obtained or some badavoided. Second, it was detailed. We did not merelygesture obscurely towards the possible existence of a

force propelling us down a dangerous slope; we

provided enough details for the reader to see thatthere would indeed be a force operating sufficienteventually to produce disaster if a certain course ofaction were taken. The two virtues I have isolatedare not unconnected: unsurprisingly, slope argu-ments with modest conclusions are easier to providewith the detail needed for adequate appraisal.We are now in a position to see why the 'Great

Argument' is not a good argument. Its conclusion ishighly immodest and it is typically undetailed. Lambused one or another version of the argument literallydozens of times in his book but nowhere gives a

description of the forces purportedly propelling us

down the slope sufficiently detailed for us to appraisethem for efficacy. Yet the conclusion - that we, as

a community, are in danger of complete moralcollapse - is one that would appear to requiredetailed and subtle substantiation.Was Lamb unaware, then, of the need to provide

evidence that the threat of a moral collapse is a

serious possibility? He was not entirely unaware ofthe need to provide evidence - he realised thatparallels between social conditions in pluralistic,democratic societies of the present and those prevail-ing in Nazi Germany are the stuff of which therelevant evidence is made. But the evidence he citesis scattered and fragmentary; a collection of parallelsdrawn from different places and times: the existenceof 'unmeltable ethnics' (ie, potential scapegoats)

in contemporary America and the British Common-wealth (5), the Milgram experiments in the USA inthe '70s in which some experimental subjectsinflicted what they believed to be great pain onothers when instructed by scientists to do so (6),jingoism in British newspapers during the Falklandswar (7). To invite us to contemplate a slide intoNazi-style atrocities on the basis of evidence pre-sented in this way is like warning us of the danger ofa bomb exploding whose explosives are in Sweden,whose casing is in the USA and whose detonator isin Rio.

What, then, is required of a successful slippery-slope argument of the ambitious kind? To besuccessful, it would simply need the backing of goodpsychology, political sociology and social history. Toachieve this would be no mean feat, of course, andwould be ofimmense value. It would provide us witha genuine insight into the preconditions and causesof communal moral deterioration. This is a phenom-enon that is not rare but commonplace - there havebeen numerous examples since the Nazis - and itwould be good to understand how and why it occurs.But the sloppy presentation of slope argumentsobscures rather than illuminates these importantprocesses.

I have suggested that ambitious slope argumentsare unlikely to be good arguments - their veryambition leads to a fatal lack of detail in formulation.To eliminate the suspicion that this is no more thana minor defect, let us examine the detailedconsiderations Lamb does supply.Lamb has a general consideration which he takes

to support his position - a worry about the framingof (laws enshrining) moral positions in vaguelanguage. Vague criteria can be stretched - presum-ably without anyone noticing - until they can bemade to apply to cases never intended by the originallegislators. There seem to be two kinds ofmechanism by which this happens. First, the stretch-ing of a boundary can be on the (hidden) agenda ofparties not actively involved in the original proposedreform. So, without needing to attribute sinistermotives to someone who advocates, say, euthanasia,on compassionate grounds, such a proposal wouldbe dangerous because of the capacity of those whowould take life for less defensible reasons to exploitthe lack of a total prohibition against killing. This isan implausible suggestion unless further supported.If legislators are aware of the kinds of active taking oflife they do not want to encourage, then they will takecare that safeguards are in place clear enough toensure that opportunistic boundary stretching willbe seen for what it is. Since almost all law is couchedin part in vague terms, this is a general problem thatthe legal system has to deal with, but I know of noevidence that the legal system has been renderedimpotent by it. In general, even the untrained jurymember is able to tell when a vague term has beenopportunistically stretched beyond the limits of

copyright. on F

ebruary 25, 2020 by guest. Protected by

http://jme.bm

j.com/

J Med E

thics: first published as 10.1136/jme.19.3.169 on 1 S

eptember 1993. D

ownloaded from

JtA Burgess 171

tolerance in force at the time. On reflection, thisshould be unsurprising. Vagueness pervades the lawbecause it pervades ordinary language and the jurorhas learnt, as we all have, to look out for opportunis-tic boundary stretching.

This brings me to the second mechanism. I thinkthat the real worry behind the example we arecurrently considering must be the fear of a slidethrough habituation into wholesale killing of a kindthe reformers never contemplated legalising. Theidea seems to be that medical professionals whoengage in euthanasia - and the general public - willcome to regard (beneficent) killing as routine. Whenthis occurs, there will be pressure for further liberal-isation until we reach a stage where courses of actionnow regarded as atrocious will then be regardedas permissible. (We will then be, in effect, at thebottom of the slope.)How likely is a process of this kind to occur? Note

first that we must suppose that the original rationalehas somehow been lost. If those who practiseeuthanasia do so for the very reasons that promptedlegislative reform, and for no other reason, then wehave no reason to fear a slide. Behind the sugges-tion, however, there seems to be another worry:people who take life for whatever reason willeventually become brutalised. Perhaps they willcome to enjoy killing as such; at least they will losethe will to be careful about establishing that aproposed killing is really beneficent. (Perhaps theybecome addicted to killing.) Now this is a hypo-thesis in empirical psychology but one which, fromthe vantage point of this armchair, seems extremelyimplausible. We know that combat soldiers aretrained killers and that part of the training consistsin deliberate and systematic dehumanisation. Wealso know that although some ex-soldiers actually dodegenerate in just the way imagined - they becomepsychopathic killers - this is a relatively unusualoutcome. (I am not of course denying that retiredcombat soldiers do suffer from psychologicalproblems directly attributable to the training andpractice of their earlier career.) Even those who aretrained to kill are usually fairly discriminating aboutwhom they kill and why: if this were not the case,soldiers would be just as likely to kill their col-leagues as the enemy. Actually, it is remarkable justhow well most military personnel are able to keeptheir killing activities quarantined from the rest oftheir lives. But if trained killers can, to a remarkableextent, be highly selective about suitable targets,why should medical practitioners slide down a slopethat soldiers can (usually) resist. The training of themedical practitioners requires no similar dehumani-sation - except the minimal training required toovercome squeamishness - and no change in train-ing would be required if we were to legaliseeuthanasia. Further, one would expect institution-alised medicine to weed out those who would kill fornon-beneficient reasons through a system of checks

and safeguards and one would expect the requiredprecautions to be enforced by law.

I conclude, then, that those who regard voluntaryeuthanasia as a step onto a slippery slope that will(probably) lead to disaster have so far failed tomake out a case that is at all convincing. Detailedempirical evidence is required and detailed empiricalevidence is conspicuously lacking. And the consider-ations just advanced suggest that the requiredevidence will not be forthcoming. Further, theancient Greeks and Romans went in for infanticide,the Eskimos practised patricide, matricide andgendercide without undergoing a gradual slide intowholesale disrespect for human life. (I am not, ofcourse, applauding or advocating these practices. Inote only that societies have been able to containsystematic killing even when it is at best onlydubiously beneficent.) Of course, these considera-tions only shift the onus of proof back onto theslope-argument theorist. But that has been preciselymy purpose.

All of this leads to the question ofwhat does causewidespread moral deterioration of the kind experi-enced in Nazi Germany. Several factors seem to meto be present in known cases of this kind. I shall firstconsider factors that might loosely be described assuitable background conditions. Second, I shallattempt to identify some of the mechanisms bywhich those conditions can be exploited to implicatethe decent and less gullible members of the society inthe slide towards genocide.

First, the presence of a ruthless totalitarian regimewith a self-serving, often religious or pseudo-scientific, ideology seems to be one of the frequentlyencountered features, even if it is not an essentialprerequisite. Clearly, total power together with amurderous hidden (or not so hidden) agenda makesthe systematic committing of atrocities possible,whether or not the general population approve ofwhat is going on. But here, whatever moral deterio-ration that has taken place has taken place before themurdering begins; the leaders of the regime havenowhere further to slide.

Second, it is important that the ideology of theruling regime incorporate an organic theory of the(dominant) social group. The social group mightsimply be identified with the state or it might be aquasi-mystical racial entity like the Volk, as in NaziGermany. To treat a social group as an organismleads those who do so to ask after the 'health' of thatorganism. This encourages the treatment of theindividual human beings who make up the group asthough they were merely functional - or (crucially)dysfunctional - parts of that organism. Thusreduced, disruptive or unproductive elements willcome to seem no more suitable as objects of moralconcern than would a diseased appendix or atumour.

Third, a general and widespread feeling ot anxietyabout the 'health' of the social organism is clearly

copyright. on F

ebruary 25, 2020 by guest. Protected by

http://jme.bm

j.com/

J Med E

thics: first published as 10.1136/jme.19.3.169 on 1 S

eptember 1993. D

ownloaded from

172 The great slippery-slope argument

conducive to moral deterioration of the kind we areconsidering. There are numerous possible (realistic)causes of anxiety of this kind; post-war demoralisa-tion in '20s Germany, fear of an alien majority incontemporary South Africa and fear of counter-revolution in numerous post-revolutionary societiesare just some of the possibilities.

Fourth, it is extremely useful (for the regime) tohave a group within the society, clearly identifiablethrough its 'otherness', to identify as the source ofthe 'disease'. The group might be a minority - Jews,Gypsies, homosexuals et al in Nazi Germany - or itmight be a disenfranchised majority, as in contem-porary South Africa or Cambodia under the KhmerRouge. Only when the target group is a minoritydoes this process appear to be correctly described asscapegoating.

This completes my list of suitable backgroundconditions. Note, however, how intimately con-nected they are: for genocide to be at all probable acombination of several conditions would seem to berequired, for there have been numerous societiesthat have exhibited one or more of these featureswithout degenerating to anything like the point thatmade the systematic, medically supervised, atrocitiesof Auschwitz possible. Clearly, if all of the precedingconditions are satisfied, it would be unsurprising if ahard-core group of supporters of the regime wereprepared to accept - even welcome - genocide as a'cure'. But how might this attitude spread to thebroader community? In particular, how might agroup of medical professionals be recruited to carryout the regime's genocidal programme?

First, it ought not to be underestimated just howefficacious the skilful and ruthless deployment ofthreats and terrorist tactics can be in implicatingunwilling members of the social group in the pro-gramme and in eliminating those courageousenough to resist even these tactics. The successfulstrategies of the Nazis and of Stalin are welldocumented.

Second, the development of a bureaucraticstructure and (preferably) a technology that facili-tates a distancing of the individual from feelings ofresponsibility for the proposed killings seems toenable otherwise decent people caught up in theprogramme to perform their functions with less guiltthan might be expected.

Finally, the ordinary mechanisms by which cor-rupt groups perpetuate themselves can lead (some-times gradually) to a broadening of the group whohave morally deteriorated: in brief, a share of powerdepends on membership in the group but member-ship in the group requires that the newcomer firstengage openly in the corrupt behaviour. Once in, thenew member gets locked in, for all the previousmembers now have on him dirt of precisely the samekind that he has (or will come to have) on them.

It is worth noting that moral deterioration neednot be, and probably seldom is, gradual. Initiation

into the rigours of army life is sudden, traumatic andbrutal and not something that creeps up on therecruit gradually and unnoticed. Contrary to thefears of proponents of the Great Argument, gradualchange is much easier to resist - for individuals, ifnot for groups - than sudden change. Further, whencrowds turn nasty and violent there is sometimes agradual build-up of tension but just as often an erup-tion can be extremely sudden. It is therefore some-thing of a mystery why purveyors of the GreatArgument seem to be more worried about gradualchange for the worse than about sudden change forthe worse.Of course, the remarks I have just made do not

constitute even a crude analysis of the causes ofmoral deterioration (8). They are intended only asfairly rough observations about the known aetiologyof that phenomenon, but they do indicate the kind ofempirical evidence which proponents of the GreatArgument might attempt to furnish, were they tomake a serious attempt to convince the sceptical. Myclaim is that until they address these issues withdetailed, subtle and scholarly work that would beseen as plausible even by the sceptical, we should notbe impressed by the Great Argument and shouldresist the conclusions about public policy theargument would appear to support.

In reaching this conclusion however, it is impor-tant to stress two points. First, I am not claiming thata combination of just some of the factors presentedought not to be cause for concern. There are manydestinations short of genocide which we should seekto avoid and if a convincing slope argument can beproduced that there is a significant danger of oursliding to such a place, then we should be wary oftaking a step in the dangerous direction. Second, Ihave been concerned here only with slides by largegroups into systematic mass killing. Considerablyless seems required for small groups and individualsto lapse in this way and less still if the killing is a 'oneoff' occurrence: it is hard to see how anyone but themost blinkered euphemist could avoid describing thebombing of Dresden or of Hiroshima as mass killingand it seems unnecessary to invoke a slippery slopeto explain how these events came about.One curiosity in the presentation of slope argu-

ments is especially worthy of note. Although Lamb,for example, presents dozens of examples in which asmall initial change in our practices purportedlymight lead gradually to disaster, no examples arepresented in which a small initial change in ourpractices might lead gradually to a moral utopia, orat least to a vastly morally superior world. Yet anypossible moral state of the world can be reachedfrom any other such state through a long enoughseries of gradual steps, just as any musical pitch canbe reached from any other through a sufficiently longglissando. The moral trombone on which Lamb andhis ilk play their tunes is apparently capable only ofdescending glissandi. I have never seen a proponent

copyright. on F

ebruary 25, 2020 by guest. Protected by

http://jme.bm

j.com/

J Med E

thics: first published as 10.1136/jme.19.3.169 on 1 S

eptember 1993. D

ownloaded from

J7A Burgess 173

of the Great Argument provide an adequateexplanation for favouring this curiously limitedinstrument. If pressed for an explanation I wouldproffer the following conjecture: those who offer theGreat Argument seem to be entirely ignorant of thevast technical literature on slippery slopes andrelated phenomena now available. In the ordinarypractitioner of applied ethics this is hardly a fault;in a proponent of the Great Argument it isunforgivable.

What, then, is really behind the worries articu-lated by Lamb and others? One is tempted to saythat the Great Argument is the last resort of theirrational conservative - and the more fanciful andparanoid the presentation, the more tempted one isto say this. But I think that there is a deeper fearlurking in the background, that does have a rationalbasis. One of the major advantages of the use ofvague language in the framing of laws and lessformal principles is that the application of those lawsand principles will change automatically as com-munity attitudes change so there will be no need tochange the law to bring it into line with thosechanged attitudes. This has evident advantages - it islargely this flexibility that makes vague language souseful to us. In a pluralistic society, however, the lawrarely if ever reflects wholly the moral position ofonegroup in society rather than another. More likely, itwill embody a compromise between the competingpositions which reflects the relative political strengthof the competing groups. Compromises achieved inthis way are rarely if ever syntheses. And a compro-mise between two coherent moral positions need notitself be a coherent moral position: witness KingSolomon's (disingenuous) proposal to resolve thedispute between the women over motherhood of thechild. But if a law reflects a compromise that isincoherent in this way, it will leave all parties dis-satisfied and newcomers confused about the ratio-nale for the law. This might well weaken themotivating force of the law (or principle), and mighteven lead to contempt for the law (or morality) as aninstitution. In extreme cases, this kind of law (orprinciple) might make no sense to anyone. Nowalthough this might lead us to be suspicious of thedesirability of pluralistic societies and of the methodof compromise to resolve disputes, the problemsraised seem to have little to do with vaguenessas such and nothing to do with slippery-slopeproblems.

I shall conclude by returning to the quotedpassage from Reichel and Dyck with which webegan. First, the worry expressed in this passageabout the preoccupation in contemporary industri-alised societies with cost-containment is real enoughbut it would be worse than fanciful to suppose thatwe can entirely avoid cost-benefit considerationswhen allocating financial resources. Resources formedical treatment and research will always be scarceand the possibilities for further reallocation of funds

from the healthy to the ill are endless and will alwaysbe with us. The decision about how much to allocateand where is unavoidable. Second, no force is pre-sented, or even hinted at, that will drive us to movefrom a concern for what is beneficial to the patient -voluntary euthanasia - to an overriding concern withwhat is beneficial to society - a desire to minimiseexpenditure on unprofitable services. Finally, let usnote how preposterous it is to invoke Lifton in sup-port of a Great Argument whose target is euthanasia.Lifton was fastidious in stressing the distinctionbetween euthanasia, as understood in the Anglo-American tradition, and 'euthanasia', as understoodby the Nazis (9). The former is concerned solelywith the alleviation of the suffering of the individual;the latter was concerned with curing a 'disease'afflicting the Volk and makes little or no sense out-side the context of an organic theory of the socialgroup. If Reichel and Dyck have identified a slidewhich we should genuinely fear, it is a slide into asociety in which a concern for cost-containmentcomes entirely to obliterate concern for the individ-ual. This would indeed be disastrous; but it wouldbe so, whether or not euthanasia were legalised alongthe way.

AcknowledgementsI should like to acknowledge that my research wassupported by an Australian National Health andMedical Research Council grant to Professor PSinger, Ms E Gaze and Dr H Kuhse. I should like tothank Helga Kuhse and Peter Singer for helpfulcomments on earlier drafts.

References and notes(1) Reichel W, Dyck A J. Euthanasia: a contemporary

moral quandary. The Lancet 1989 Dec 2: 1321-1323: page 1322.

(2) See, for example Capron A M. The right to die:progress and peril. Euthanasia review 1987; 2: 41-59:page 53ff.

(3) Lamb D. Down the slippery slope: arguing in appliedethics. London: Croom Helm, 1988.

(4) In view of the fact that dozens - possibly hundreds -have recently produced versions of what I have beencalling the Great Argument, an explanation is requiredofmy reasons for choosing Reichel, Dyck and Lamb astargets. Reichel and Dyck are of interest for tworeasons. First, they have produced an argument that ismore detailed than most. Second, they were preparedto advance a crude slope argument, even though theywere aware of literature that should have alerted themto its crudity. In the case of Lamb, the interest lies inthe fact that he was sufficiently impressed with theGreat Argument to structure an entire book around it.

(5) See reference (3): 19.(6) See reference (3): 36-37.(7) See reference (3): 37.(8) In compiling the list, I have drawn heavily for confir-

mation of my own intuitions and, in some places forinspiration, on Robert Jay Lifton, The Nazi doctors,

copyright. on F

ebruary 25, 2020 by guest. Protected by

http://jme.bm

j.com/

J Med E

thics: first published as 10.1136/jme.19.3.169 on 1 S

eptember 1993. D

ownloaded from

174 The great slippety-slope argument

New York: Basic Books, 1986, in particular, but alsoon Elias Canetti, Crowds and power, New York: Viking,1962. When I first decided that an antidote to theGreat Argument was long overdue, I thought that thedecisive step would be to point out the existence ofsubtle, modest, detailed and cautious analyses of theaetiology of genocide and to contrast these with thesloppy and unscholarly fear-mongering of those whorely on the Great Argument. Dream on. The quote

from Reichel and Dyck with which we began actuallycontains a footnote to Lifton. The point stressed byLifton that even after one has made a detailed study ofthe Nazi period, there is something about social groupsand the darker side of the human psyche which makesthat period, and other such episodes, deeply mysterious- perhaps ultimately inexplicable - seems completelyto have passed those authors by.

(9) See reference (8): 46.

News and notes

Quality '93: Raising Quality in the NHS: What Progress?

Quality '93, to be held on 11 November atThe Brewery, London EC 1, follows thesuccess of Raising Quality in the NHS in March1992.

Quality '93 is being organised by the BMA,the BMJ, the Kings Fund, the College of Healthand Quality in Health Care. The meeting willreview progress with raising quality in the NHSand also look at what's new in raising quality. A

particular focus will be on involving patients inraising quality.The meeting is open to doctors, nurses, all

health professionals, managers, politicians,researchers, policy makers and members of thepublic.

For further details contact: Pru Walters, BMAHouse, Tavistock Square, London WCIH 9JP,Telephone: 071 383 6518.

copyright. on F

ebruary 25, 2020 by guest. Protected by

http://jme.bm

j.com/

J Med E

thics: first published as 10.1136/jme.19.3.169 on 1 S

eptember 1993. D

ownloaded from