16.雲端虛擬主機為雲端運算的哪一種基本服務模式？(A)軟體即服務(Software as a Service, SaaS)(B)平台即服務(Platform as a Service, PaaS)(C)架構即服務(Infrastructure as a Service, IaaS)(D)數據即服務(Data as a Service, DaaS)