Customers use infrastructure and programming tools supported by the cloud service provider to develop their own applications. For example,

Salesforce.com's

Force.com allows developers to build applications that are hosted on its servers as a service. This is called

A$.$ Capacity as a service $($CaaS$)$

B$.$ Platform as a service $($PaaS$)$

C$.$ DevOps

D$.$ Infrastructure as a service $($IaaS$)$

E$.$ Software as a service $($SaaS$)$