题目内容：
根据以下材料回答题 Thousandsofyearsagomanusedhandyrocksforhissurgicaloperations．Laterheusedsharpbonesorhorns,metalknivesandmorerecently,rubberandplastic．Inthe1960sanewtoolwasdeveloped,onewhichwas,firstofall,tobeofgreatpracticalusetothearmedforcesandindus-try,butwhichwasalsotorevolutionizetheartandscienceofsurgery．
Thetoolisthelaseranditisbeingusedbymoreandmoresurgeonsallovertheworld．Asweallknow,lightishot,andanysourceoflightwillgivewarmth．Butlightisusuallyspreadoutoverawidearea．Thelightinalaserbeam,however,isconcentrated．Thismeansthatalightwithnomorepowerthanthatproducedbyanordinaryelectriclightbulbbecomesintenselystrongasitisconcentratedtoapinpoint-sizedbeam．
Experimentswiththesepinpointbeamsshowedresearchersthatdifferentenergysourcespro-ducebeamsthathaveaparticulareffectoncertainlivingcells．Itisnowpossibleforeyesurgeonstooperateonthebackofhumaneyewithoutharmingthefrontoftheeye,simplybypassingalaserbeamrightthroughtheeye-ball．Operationswhichonceleftpatientsexhaustedandinneedoflongperiodofrecoverytimenowleavethemfeelingrelaxedandcomfortable．
Therapiddevelopmentoflasertechniquesinthepasttenyearshasmadeitclearthatthefutureislikelytobeveryexciting．Perhapssomecancerswillbetreatedwithlaserinawaythatmakessurgerynotonlysaferbutalsomoreeffective．
Whichofthefollowingwouldbeappropriatetodescribetheinstrumentsofsurgicalopera-tionsupuntil1960s? A．Traditional．
B．Complicated．
C．Remarkable．
D．Revolutionary．
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答案解析：