Explanation
Review of security metrics trends is the best evidence to senior management that security control performance has improved because it helps to measure and demonstrate the effectiveness and efficiency of the security controls over time. Security metrics are quantitative or qualitative indicators that provide information about the security status or performance of an organization, system, process, or activity. Security metrics can be used to evaluate the implementation, operation, and outcome of security controls, such as the number of vulnerabilities detected and remediated, the time to respond and recover from incidents, the compliance level with security policies and standards, or the return on security investment. Review of security metrics trends helps to identify and communicate the progress, achievements, and challenges of the security program, as well as to support decision making and continuous improvement. Therefore, review of security metrics trends is the correct answer.
References:
* https://www.bitsight.com/blog/importance-continuous-improvement-security-performance-management
* https://www.isaca.org/resources/isaca-journal/issues/2020/volume-6/key-performance-indicators-for-secur
* https://www.nist.gov/news-events/news/2021/09/dhs-nist-coordinate-releasing-preliminary-cybersecurity-p