A cloud service provider offers web mail services to its subscribers. Which cloud service model does this depict?

CaaS

MaaS

PaaS

SaaS

I’d say PaaS ... Platform as a Service (PaaS) or application platform as a Service (aPaaS) or platform base service is a category of cloud computing services that provides a platform allowing customers to develop, run, and manage applications without the complexity of building and maintaining the infrastructure typically associated with developing and launching an app.