Cloudcomputingisaphraseusedtodescribeavarietyofcomputingconcepts

Cloudcomputingisaphraseusedtodescribeavarietyofcomputingconceptsthatinvolvealargenumberofcomputers()throughareal-timecommunicationnetworksuchastheInternet．Inscience，cloudcomputingisa()fordistributedcomputingoveranetwork，andmeansthe()torunaprogramorapplicationonmanyconnectedcomputersatthesametime．Thearchitectureofacloudisdevelopedatthreelayers：infrastructure，platform，andapplication，Theinfrastructurelayerisbuiltwithvirtualizedcompute，storage，andnetworkresources．Theplatformlayerisforgeneral-purposeandrepeatedusageofthecollectionofsoftwareresources．TheapplicationlayerisformedwithacollectionofallneededsoftwaremodulesforSaaSapplications．Theinfrastructurelayerservesasthe(请作答此空)forbuildingtheplatformlayerofthecloud．Inturn，theplatformlayerisafoundationforimplementingthe()layerforSaaSapplications．

A.network

B.foundation

C.software

D.hardware

正确答案是B