题目内容：
Ihavebeenconsistentlyopposedtofeedingababyregularly.Asadoctor,motherandscientistinchilddevelopmentIbelievethereisnothingtorecommendit,fromthebaby’spointofview.Mothers,doctorsandnursesalikehavenoideaofwhereababy’sbloodsugarlevellies.Allweknowisthatalowlevelisharmfultobraindevelopmentandmakesababyeasilyannoyed.Inthisstate,thebabyisdifficulttocalmdownandsleepisimpossible.Thebabyasksforattentionbycryingandsearchingforfoodwithitsmouth.
Itisnotjustunkindbutalsodangeroustosayafour-hourlyfeedingschedulewillmakeababysatisfied.Thefirstoftheexpertstoadvocateastrictclock-watchingschedulewasDr.FredericTrubyKingwhowasagainstfeedinginthenight.I’veneverheardanythingsoridiculous.Babyfeedingshouldn’tfollowatimetablesetbythemum.Whatisimportantisfeedingababyinthebestway,thoughitmaycausesomeinconvenienceinthefirstfewweeks.
Well,atlastwehavecopper-bottomedresearchthatsupportsdemandfeedingandpointsouttheweaknessesofstrictlytimedfeeding.Theresearchfindsoutthatbabieswhoarefedondemanddobetteratschoolatage5,7,11and14,thanbabiesfedaccordingtotheclock.Bytheageof8,theirIQ（智商）scoresarefourtofivepercenthigherthanbabiesfedbyarigidtimetable.ThisresearchcomesfromOxfordandEssexUniversityusingasample（样本）of10,419childrenbornintheearly1990s,takingaccountofparentaleducation,familyincome,achild’ssexandage,themother’shealthandfeelingstyle.Theseresultsdon’tsurpriseme.Feedingaccordingtoschedulerunstheriskofharmingtherapidlygrowingbrainbytakingnoaccountofsinkingbloodsugarlevels.
Ihopethisresearchwillputanendtoadvocatingstrictlytimedbabyfeelingpractices.
根据以上内容，回答题。AccordingtoParagraph2,onereasonwhyababycriesisthatitfeels______. A．sick
B．upset
C．sleepy
D．hungry
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