rEmotE ADministrAtion typEs ArE An ExAmplE oF onE kinD oF {{u}} (71) {{/u}}mAliCious soFtwArE, thE trojAn horsE, or morE simply trojAn. thE purposE oF thEsE progrAms isn’t rEpliCAtion, {{u}} (72) {{/u}}to pEnEtrAtE AnD Control. thAt mAsquErADE As onE thing whEn in FACt thEy ArE somEthing ElsE, usuAlly somEthing DEstruCtivE. thErE ArE A numBEr oF kinDs oF trojAns, inCluDing spyBots, {{u}} (73) {{/u}} rEport on thE wEB sitEs A ComputEr usEr visits, AnD kEyBots or kEyloggErs, whiCh rECorD AnD rEport thE usEr’s kEystrokEs in orDEr to DisCovEr pAssworDs AnD othEr ConFiDEntiAl inFormAtion. rAts AttEmpt to givE A rEmotE intruDEr ADministrAtivE Control oF An inFECtED ComputEr. thEy work As {{u}} (74) {{/u}}pAirs. thE sErvEr rEsiDEs on thE inFECtED mAChinE, whilE thE CliEnt rEsiDEs ElsEwhErE, ACross thE nEtwork, whErE it’s AvAilABlE to A rEmotE intruDEr. using stAnDArD tCp/ip or uDp protoCols, thE CliEnt sEnDs instruCtions to thE sErvEr. thE sErvEr DoEs {{u}} (75) {{/u}} it’s tolD to Do on thE inFECtED ComputEr.

A．nonvirAl
B、unvirAl
C．invirAl
D．ABvirAl