Cloudcomputingisaphraseusedtodescribeavarietyofcomputingconceptsthatinvolvealargenumberofcomputers()throughareal-timecommunicationnetworksuchastheInternet.In science,cloudcomputingisa()fordistributedcomputingoveranetwork,andmeansthe()torunaprogramorapplicationonmanyconnectedcomputersatthesametime. Thearchitectureofacloudisdevelopedatthreelayers:infrastructure,platform,andapplication.Theinfrastucturelayerisbuiltwithvirtualizedcomputestorageandnetworkresources.Theplatformlay-erisforgeneral-purposeandrepeatedusageofthecollectionofsoftwareresources.TheapplicationlayerisformedwithacollectionofallneededsoftwaremodulesforSaaSapplications.Theinfrastucturelayerservesasthe()forbuildingtheplatformlayerofthecloud.Inturn,theplatformlayerisfounda-tionforimplementingthe(请作答此空)layerforSaaSapplication
A.resource B.service C.application D.software正确答案C
