The correct option is To evaluate whether implemented security controls are operating effectively.

This Security Control Assessment step in the NIST Risk Management Framework is intended to verify that controls are implemented correctly and operate as intended in the system environment. Assessors gather and test evidence to determine control effectiveness and to identify weaknesses that affect the system security posture so that authorizing officials can make informed, risk based decisions.

To confirm that the system complies with applicable laws and policies is not the primary objective. Compliance activities may be part of broader review and audit processes, but the assessment specifically focuses on whether controls work as designed rather than serving as a legal or policy compliance certification.

To identify which security controls are required for the system is incorrect because control selection occurs earlier in the RMF during categorization and tailoring. The assessment assumes controls have been selected and implemented and then evaluates their operation.

To create and apply plans to reduce the system risks is not the main goal of the assessment. Creating and implementing remediation or mitigation plans happens after the assessment when findings are addressed, for example through plans of action and milestones and other risk response actions.

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