Explanation
According to the Certified Information Security Manager (CISM) Study Guide, the greatest challenge to the recovery of critical systems and data following a ransomware incident is the availability and integrity of backups. If the backups are unavailable or corrupt, it becomes much more difficult, if not impossible, to recover the systems and data. This highlights the importance of regularly testing and verifying the backup and recovery process to ensure that the backups are available and can be used in the event of an incident.
Additionally, it is important to ensure that backups are stored securely and off-line to prevent them from being encrypted or deleted by an attacker.

Explanation
The primary purpose for continuous monitoring of security controls is to ensure the effectiveness of controls.
This involves regularly assessing the controls to ensure that they are meeting their intended objectives, and that any potential weaknesses are identified and addressed. Continuous monitoring also helps to ensure that control gaps are minimized, and that systems are available and aligned with compliance requirements.