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.
Reference:
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-security-governance-part-2
https://www.nist.gov/news-events/news/2021/09/dhs-nist-coordinate-releasing-preliminary-cybersecurity-performance-goals.

Centralization of information security management results in greater uniformity and better adherence to security policies. It is generally less expensive to administer due to the economics of scale. However, turnaround can be slower due to the lack of alignment with business units.

An advanced persistent threat (APT) is a stealthy and sophisticated attack that aims to compromise and maintain access to a target network or system over a long period of time, often for espionage or sabotage purposes. APTs are difficult to detect by conventional security tools, such as antivirus or firewalls, that rely on signatures or rules to identify threats. Therefore, the best way to monitor for APTs is to search for anomalies in the environment, such as unusual network traffic, user behavior, file activity, or system configuration changes, that may indicate a compromise or an ongoing attack. Reference: https://www.isaca.org/credentialing/cism https://www.nist.gov/publications/information-security-handbook-guide-managers