Representational State Transfer (REST) uses TLS for communication over secured channels.
Although REST also supports SSL, at this point SSL has been phased out due to vulnerabilities and has been replaced by TLS.

Explanation
Within a SaaS implementation, the cloud customer licenses the use of the software from the cloud provider because SaaS delivers a fully functional application to the customer. With SaaS, the cloud provider is responsible for the entire software application and any necessary infrastructure to develop, run, and maintain it. The purchasing, development, and maintenance are fully the responsibility of the cloud provider.

Explanation
The question is describing the Infrastructure as a Service (IaaS) cloud offering, and as such, the volume and object storage types will be available to the customer. Structured and unstructured are storage types associated with PaaS, and although the other answers present similar-sounding storage types, they are a mix of real and fake names.

Billing for an audit, or other cost-related items, would not be part of an audit scope statement and would instead be handled prior to the actual audit as part of the contract between the organization and auditors.
Reports, exclusions to the scope of the audit, and required certifications on behalf of the systems or auditors are all crucial elements of an audit scope statement.