How often will the security controls be reviewed by NIST and revised if necessary?

The correct answer is appropriate because the National Institute of Standards and Technology (NIST) emphasizes the importance of reviewing security controls under specific circumstances that reflect changes in an organization’s environment or risk posture. According to NIST guidelines, a review should occur after any significant changes to the system, including updates in technology, changes in the operational environment, or alterations in business processes. This approach ensures that security controls remain effective and relevant in the face of evolving threats and vulnerabilities, facilitating a proactive rather than reactive security posture.

While regular reviews, such as annual or bi-annual assessments, may be part of a broader security strategy, the critical point here is that NIST prioritizes the need for immediate evaluation following significant changes. This focus on situational adjustments aligns with the dynamic nature of security risks and the necessity for organizations to be agile in their defense measures.