正解:A
Comprehensive and Detailed Step-by-Step Explanation:
When storage space is limited,incremental backupsare the most efficient because they store only the changes made since the last backup, reducing storage requirements.
* Option A (Correct):Incremental backupsonly store data that has changed since the last backup, significantly reducing storage usage while maintaining a historical record of changes.
* Option B (Incorrect):Mirror backupscreate an exact copy of the entire system, consuming significant storage space andnot retaining historical versions.
* Option C (Incorrect):Full backupscapture everything and require large amounts of storage, making them impractical for space-constrained environments.
* Option D (Incorrect):Annual backupsrefer to frequency rather than method. They do not inherently optimize storage usage.
Reference:ISACA CISA Review Manual -Domain 4: Information Systems Operations and Business Resilience- Covers backup strategies, storage management, and disaster recovery.