Which backup type backs up only data that has changed since the last backup of any type?

• A. Full
• B. Differential
• C. Incremental
• D. Mirror

Answer: (C)

Incremental backups capture only the data that has changed since the last backup of any type. After an initial full backup, each subsequent backup records only the new or modified data since the previous backup, keeping each backup small and fast. This is different from full backups (which copy everything every time) and differential backups (which copy everything changed since the last full backup, growing larger over time). A mirror is a live, exact copy rather than a time-stamped backup chain. So, for minimizing backup size while still supporting restoration, incremental backups are the right fit, with the trade-off being that restoring requires the last full backup plus every incremental backup in the chain.