Cloudcomputingisaphraseusedtodescribeavarietyofcomputingconceptsthatinvolvealargenumberofcomputers___71___throughareal-timecommunicationnetworksuchastheInternet.Inscience,cloudcomputingisa___72___fordistributedcomputingoveranetwork,andmeansthe___73___torunaprogramorapplicationonmanyconnectedcomputersatthesametime. Thearchitectureofacloudisdevelopedatthreelayers:infrastructure,platform,andapplication.Theinfrastucturelayerisbuiltwithvirtualizedcomputestorageandnetworkresources.Theplatformlay-erisforgeneral-purposeandrepeatedusageofthecollectionofsoftwareresources.TheapplicationlayerisformedwithacollectionofallneededsoftwaremodulesforSaaSapplications.Theinfrastucturelayerservesasthe___74___forbuildingtheplatformlayerofthecloud.Inturn,theplatformlayerisfounda-tionforimplementingthe__请作答此空___layerforSaaSapplication.
A.resource B.service C.application D.software正确答案C