Today,asineveryotherdayoftheyear,morethan3000U.S.adlescentswillsmoketheirfirstcigaretteontheirwaytobecomingregularsmokersasadults.Duringtheirlifetime,itcanbeexpectedthatofthese3000about23willbemurdered,30willdieintrafficaccidents,andnearly750willbekilledbyasmoking-relateddisease.Thenumberofdeathsattributedtocigarettesmokingoutweithtsallotherfactors,whethervoluntaryorinvoluntary,asacauseofdeath.Sincethelate1970s,whendailysmokingamonghighschoolseniorsreached30precent,smokingratesamongyouthhavedeclined.Whilethedeclineisimpressive,severalimportantissuesmustberaised.First,inthepastseveralyears,smokingratesamongyouthhavedeclinedverylittle.Second,inthelate1970s,smokingamongmalehighschoolseniorsexceededthatamongfemalebynearly10percent.Thestatisticisreversing.Third,severalrecentstudieshaveindicatehighschooldropoutshaveexcessivelyhighsmokingrates,asmuchas75percent.Finally,thouthsignificantdeclinesinadolescentsmokinghaveoccurredinthepastdecade,nodefinitereasonsforthedeclineexist.Withinthiscontext,theNaionalCancerInstiute(NCI)beganitscurrentefforttodeterminethemosteffecivemeasurestoreducesmokingleveslamongyouth.Whatisimpliedbutnotstatedbytheauthoristhat().
A. smokingratesamongyouthhavedeclinedverylittle
B. therearenowmorefemalethanmalesmokersamonghighschoolseniors
C. highsmokingratesareduetotheinceaseinwealth
D. smokingathighschoolarefromlowsocio-economicbackgrounds