A cloud access security broker (CASB) is a security solution that monitors and controls the use of cloud-based services and applications. A CASB can provide data loss prevention (DLP) capabilities for sensitive data that is being stored in the cloud, such as encryption, masking, tokenization, or redaction. A CASB can also enforce policies and compliance requirements for cloud usage, such as authentication, authorization, auditing, and reporting. The other options are not appropriate solutions for controlling sensitive data in the cloud. Reference: CompTIA Cybersecurity Analyst (CySA+) Certification Exam Objectives (CS0-002), page 14; https://docs.microsoft.com/en-us/cloud-app-security/what-is-cloud-app-security