CloudTrail is the appropriate choice for monitoring and logging user actions and resource changes over time, vital for handling sensitive information like PHI. It ensures that actions taken by users, roles, or AWS services are recorded, which is fundamental for maintaining stringent access logs required by compliance standards, such as those related to healthcare information.

The use of Inspector would not fulfill the requirement as its use case is security assessment for applications, not detailed logging of data access. Config helps monitor resource states and changes but does not provide the granular action-level logging required for compliance audits associated with healthcare data. CloudWatch primarily focuses on performance monitoring rather than user access and interaction logs.