In the passage, the author is primarily concerned with

A．presentingahypothesisanddescribingcompellingevidenceinsupportofit
B．raisingaquestionanddescribinganimportantdiscoverythatledtoananswer
C．showingthatacertainautoimmunediseasecannotyetbetreatedeffectivelywithdrugs
D．explainingwhatevidenceexistsforanautoimmunecausefornarcolepsy
E．discussingtheimportanceofresearchonanimalsforthestudyofhumandisease