Cloudcomputingisaphraseusedtodescribeavarietyofcomputingconceptsthatinvolvealargenumberofcomputers(请作答此空)throughareal-timecommunicationnetworksuchastheInternet.Inscience,cloudcomputingisa()fordistributedcomputingoveranetwork,andmeansthe()torunaprogramorapplicationonmanyconnectedcomputersatthesametime.Thearchitectureofacloudisdevelopedatthreelayers:infrastructure,platform,andapplication,Theinfrastructurelayerisbuiltwithvirtualizedcompute,storage,andnetworkresources.Theplatformlayerisforgeneral-purposeandrepeatedusageofthecollectionofsoftwareresources.TheapplicationlayerisformedwithacollectionofallneededsoftwaremodulesforSaaSapplications.Theinfrastructurelayerservesasthe()forbuildingtheplatformlayerofthecloud.Inturn,theplatformlayerisafoundationforimplementingthe()layerforSaaSapplications.
A.connected
B.imlemented
C.optimized
D.Virtualized
正确答案是A