题目内容：
根据下面内容，回答题
Disagreementsamongeconomistsarelegendary,butnotontheissueoffreetrade．Arecentsurveyofprominenteconomistsbothconservativeandliberalconcludedthataneconomistwhoar-guesforrestrictinginternationaltradeisalmostascommontodayasaphysicianwhofavorsleech-ing.
Whytheconsensus?Internationalfreetrade,economistsagree,makespossiblehigherstan-
dardsoflivingallovertheglobe.
Thecaseforfreetraderestslargelyonthisprinciple:aslongastradeisvoluntary,bothpart-nersbenefit,otherwisetheywouldn'ttrade．Thebuyerofashirt,forexample,valuestheshirtmorethanthemoneyspent,whilethesellervaluesthemoneymore．Botharebetteroffbecauseofthesale．Moreover,itdoesn'tmatterwhethertheshirtsalesmanisfromtheUnitedStatesorHongKong(oranywhereelse).
ThevastmajorityofAmericanmanufacturesfaceinternationalcompetition．Thiscompetitionforcescompaniestoimprovequalityandcutcosts．Bycontrast,protectionismencouragesmonopoly,lowerqualityandhigherprices.
Americanspayanenormouspriceforprotectionismover$60billionayear,or$1000forafamilyoffour．Thankstoprotectionism,forexample,Americanconsumerspaytwicetheworldpriceforsugar.
Freetradealsomakestheworldeconomymoreefficient,byallowingnationstocapitalizeontheirstrengths．TheUnitedStateshasanadvantageinfoodproduction,forinstance,whileSaudiArabiahasanadvantageinoil．TheSaudiscouldundertakemassiveirrigationtobecomeself-suf-ficientinfood,butitismoreeconomicalforthemtoselloilandpurchasefoodfromus．Similarly,
wecouldbecomeself-sufficientinpetroleumbysqueezingmoreoutofoilshale．ButitismuchlesscostlytobuysomeofouroilfromSaudiArabia．Tradebetweenourtwocountriesimprovesthestandardoflivinginboth.
Protectionismisbothwastefulandunjust．Ittaxesmostheavilythepeoplewhocanleastaffordit．Thus,tariffsthatraisethepriceofshoesburdenthepoormorethan.therich．Despitethepow-erfulcaseforfreetrade,theUnitedStatesandtherestoftheworldhavealwaysbeenprotectionisttosomedegree．Thisisbecausefreetradebenefitsthegeneralpublic,whileprotectionismbenefitsspecialinterestgroups,whicharebetterorganized,betterfinancedandmoreinformed．Tomakemattersworse,muchofwhatwehearonthisissueismisinformationspreadbythespecialintereststhemselves.
Theeconomists A．agreeontherestrictionofinternaltrade
B．disagreewhethertorestrictfreetradeornot
C．holddifferentargumentsbecauseoftheirdifferentinterests
D．agreeonfreetrade.
参考答案：
答案解析：