阅读下列四篇短文，从每小题后所给的A,B,C或D四个选项中，选出最佳选项。KingdaKa,thetallestrollercoaster（过山车）onEarth,dropsitspassengersalife-flashing418feet.FerrariWorld'sFormulaRossa,thefastest,takesriders'breathawayatspeedsofupto150mph.BRCImaginationArts,aSouthernCaliforniadesignfirm,hasproposedsomethingentirelynew:aridethatcreatesthesensationofzerogravityforuptoeightsecondsatatime.BRCdrewitsconceptfromthe"VomitComet,"theplaneNASAusestotrainastronauts.Itsproposedtheme-parkridewouldtravelupandthenback,similartotheexisting"Superman:EscapefromKrypton"coasteratSixFlagsMagicMountaininCalifornia.ButunlikeSupermanandotheropen-carcoasters,thevomit-cometridewouldbefullyenclosed.Riderswouldenjoytheillusionoffloatingwithinastablechamber.Tocreatethatillusion,aspecialmotorsystemwouldspeedcoastersupthetrackwithgreatprecision（精确度）.Asthecoasterapproachedatopspeedofmorethan100mph,itwouldsuddenlyandeversoslightlyslowdown—justenoughtothrowthepassengersupfromtheirseatsandthenquicklyadjustitsspeedtoflyinformationwithandaroundthepassengers.Asthecoasterreachedthetopofthetrackandbegantodropbackdown,thecomputersystemwouldcontinuetomatchitsspeedtothatofthefallingpassengers,extendingthesensationofweightlessnessforseveraladditionalseconds,andfinallyrapidlyslowdowntoastopbackatthebasestation.Rollercoasterstypicallycostnomorethan$30million,butthezero-gravityridewouldcost$50millionormore,toalargeextentbecausetheprecision-responsepropulsionsystem（推进系统）issocomplex.Butifsomeoneweretowriteachecktoday,Rogerssays,hiscompanycouldbesendingridersonweightlessjourneysbytheendof2014.1.WhatmakesBRC'scoasterdifferent?A.It'sthetallestrollercoasterintheStates.B.It'sthefastestrollercoasteronEarth.C.Itcanbringasensationofzerogravitytoitsriders.D.ItisaNASAproduct.2.WhywouldpeopleinBRC'scoasterhaveanillusionoffloatinginthechamber?A.Becauseit'sdesignedwiththeinspirationofSuperman.B.Becauseaspecialfunctioningmotorsystemisappliedtoit.C.Becausethecoastercanapproachatopspeedofmorethan100mph.D.Becausethecoasterwouldcost$20millionmorethannor