What does a differential backup copy?

What does a differential backup copy?

• A. They copy all data every time
• B. They copy changes since last backup
• C. They copy data until storage runs out
• D. They copy changes since last full backup

Answer: (D)

Differential backups capture all changes made since the last full backup. After you run a full backup, each differential backup includes every file that has changed or been added since that full backup, so differentials accumulate new changes until another full backup resets them. When restoring, you use the most recent full backup plus the latest differential to reconstruct the state at that time. That’s why this option matches the definition of a differential backup. The other descriptions point to a full backup (copying everything) or to an incremental approach (copying changes since the last backup, not since the last full), or aren’t a recognized backup type.

Differential backups capture all changes made since the last full backup. After you run a full backup, each differential backup includes every file that has changed or been added since that full backup, so differentials accumulate new changes until another full backup resets them. When restoring, you use the most recent full backup plus the latest differential to reconstruct the state at that time. That’s why this option matches the definition of a differential backup. The other descriptions point to a full backup (copying everything) or to an incremental approach (copying changes since the last backup, not since the last full), or aren’t a recognized backup type.