Drunkendriving,sometimescalledAmerica'ssociallyacceptedformofmurder,hasbecomeanationalepidemic.EveryhourofeverydayaboutthreeAmericansonaveragearekilledhy drunkendrivers,addingupanincredible350,000overthepastdecade. Adrunkendriverisusuallydefinedasonewitha0.10bloodalcoholcontentorroughlythreebeers,glassesofwineorshotsofwhiskydrunkwithintwohours.HeavydrinkingusedtobeanacceptablepartoftheAmericanalcoholimageandjudgeswerelenientinmostcourts,butthedrunkenslaughterhasrecentlycausedsomanywell-publicizedtragedies,especiallyinvolvingyoungchildren,thatpublicopinionisnolongersotolerant. Twentystateshaveraisedthelegaldrinkingageto21,reversingatrendinthe1960storeduceitto18.AfterNewJerseylowereditto18,thenumberofpeoplekilledby18to20-year-olddriversmorethandoubled,sothestaterecentlyuppeditbackto21.Reformers,however,fearraisingthedrinkingagewillhavelittleeffectunlessaccompaniedbyeducationalprogramstohelpyoungpeopletodevelop"responsibleattitudes"aboutdrinkingandteachthemtoresistpeerpressuretodrink. Toughnewlawshaveledtoincreasedarrestsandinmanyareasalready,toamarkeddeclineinfatalities.Somestatesarealsopenalizingbarsforservingcustomerstoomanydrinks. Asthefatalitiescontinuetooccurdailyineverystate,someAmericansareevenbeginningtospeakwellofthe13years'nationalprohibitionofalcoholthatbeganin1919,whichPresidentHoovercalledthe"nobleexperiment".Theyforgetthatlegalprohibitiondidn'tstopdrinking,butencouragedpoliticalcorruptionandorganizedcrime.Aswiththeboomingdrugtradegenerally,thereisnoeasysolution. Therulethatonlypeopleabove21yearsofagecandrink__________.
A.is a new law promoted by the twenty states
B.had been once adopted before the 1960s
C.has been enforced since the prohibition of alcohol
D.will be carried out all over the country
正确答案是B