A vendor risk assessment is a process of evaluating and managing the risks associated with outsourcing IT services or functions to a third-party provider, such as a cloud service provider.
One of the most important documents to request from a cloud service provider during a vendor risk assessment is an independent audit report. This is a report that provides an objective and reliable assurance on the quality, security, and performance of the cloud service provider’s operations, processes, and controls, based on the standards and criteria established by an independent auditor or a recognized authority, such as ISACA, ISO, NIST, etc.
An independent audit report helps to verify the compliance and effectiveness of the cloud service provider’s risk management practices, identify any gaps or issues that may affect the service delivery or security, and recommend improvements or corrective actions.
The other options are not the most important documents to request from a cloud service provider during a vendor risk assessment. They are either secondary or not essential for vendor risk management.
The references for this answer are:
Risk IT Framework, page 22
Information Technology & Security, page 16
Risk Scenarios Starter Pack, page 14