What Is the Difference Between Cloud Computing and Software as a Service

What is the difference between cloud computing and software as a service (Saas) ?

A) Software and processing are offered by cloud computing companies, while SaaS companies focus on data storage.
B) Data and services are stored in the cloud, while software and processing are offered by SaaS companies.
C) The two terms are interchangeable.
D) Cloud computing is free while SaaS is paid for by users.
E) Cloud computing is paid for by users while SaaS is free.