A mirror backup is a type of backup that creates an exact copy of the source data to the destination, without using any compression or encryption. A mirror backup is the best backup scheme to recommend given the need for a shorter restoration time in the event of a disruption, because it allows for the fastest and easiest recovery of data. A mirror backup does not store any previous versions of the files, so it only reflects the current state of the source data. Therefore, a mirror backup requires less storage space than a full backup, but more than an incremental or differential backup.
A differential backup is a type of backup that stores the changes made to the source data since the last full backup. A differential backup requires less storage space and time than a full backup, but more than an incremental backup. However, a differential backup also requires more time and resources to restore than a mirror or full backup, because it needs to combine the last full backup and the latest differential backup to recover the data.
A full backup is a type of backup that copies all the files and folders from the source data to the destination, regardless of whether they have changed or not. A full backup provides the most complete protection of data and the simplest recovery process, but it also requires the most storage space and time to perform. A full backup is usually done periodically, such as weekly or monthly, and followed by incremental or differential backups.
An incremental backup is a type of backup that stores the changes made to the source data since the last backup, whether it was a full or an incremental backup. An incremental backup requires the least storage space and time to perform, but it also requires the most time and resources to restore, because it needs to combine all the previous backups in chronological order to recover the data.

The most concerning issue associated with a data center's CCTV surveillance cameras is that the recordings are not regularly reviewed. This means that any unauthorized access, theft, vandalism, or other security incidents may go unnoticed and unreported. CCTV recordings are a valuable source of evidence and deterrence for data center security, and they should be monitored and audited periodically to ensure compliance with policies and regulations. If the recordings are not reviewed, the data center may face legal, financial, or reputational risks in case of a security breach or an audit failure.
The other options are less concerning because they do not directly affect the security of the data center. CCTV cameras are not required to be installed in break rooms, as they are not critical areas for data protection.
CCTV records can be deleted after one year, as long as they comply with the data retention policy of the organization and the applicable laws. CCTV footage does not need to be recorded 24 x 7, as long as there is sufficient coverage of the data center during operational hours and when access is granted to authorized personnel. References:
* ISACA Journal Article: Physical security of a data center1
* Data Center Security: Checklist and Best Practices | Kisi2
* Video Surveillance Best Practices | Taylored Systems

Impact assessment is an activity that occurs during the issues management process for a system development project. Issues management is a process of identifying, analyzing, resolving, and monitoring issues that may affect the project scope, schedule, budget, or quality. Impact assessment is a technique of evaluating the severity and priority of an issue, as well as its implications for the project objectives and deliverables. The other options are not activities that occur during the issues management process, but rather related to other processes such as contingency planning, configuration management, or help desk management. References:
* CISA Review Manual (Digital Version), Chapter 4, Section 4.3.31
* CISA Review Questions, Answers & Explanations Database, Question ID 217

The primary reason for an IS audit manager to review the work performed by a senior IS auditor prior to presentation of a report is to ensure the conclusions are adequately supported. The IS audit manager is responsible for overseeing and supervising the audit process, ensuring the quality and consistency of the audit work, and approving the audit report and recommendations. The IS audit manager should review the work performed by the senior IS auditor to verify that the audit objectives, scope, and criteria have been met, that the audit evidence is sufficient, reliable, and relevant, and that the audit conclusions are logical, objective, and based on the audit evidence. The IS audit manager should also ensure that the audit report is clear, concise, accurate, and complete, and that it communicates the audit findings, conclusions, and recommendations effectively to the intended audience. The other options are not the primary reason for an IS audit manager to reviewthe work performed by a seniorIS auditor prior to presentation of a report, because they either relate to specific aspects or stages of the audit work rather than the overall outcome, or they are part of the senior IS auditor's responsibility rather thanthe IS audit manager's. References: CISA Review Manual (Digital Version)
1, Chapter 2, Section 2.2.5