Final answer:
An incremental backup saves only the changes made since the last full backup.
Step-by-step explanation:
The correct answer is incremental backup. An incremental backup saves only the changes made to the data since the last full backup.
This type of backup works by identifying and backing up only the files that have been modified or created since the last backup, which makes it more efficient in terms of storage space and time required for the backup.
The type of backup that saves only the changes made since the last full backup is known as an incremental backup. In contrast to a full backup which copies all data, an incremental backup will only back up data that has changed since the previous backup, whether that last backup was a full or another incremental one.
This can save a significant amount of time and storage space. On the other hand, a differential backup saves changes made since the last full backup, but each time it runs, it will include all changes since that last full backup, not just the changes since the last differential backup.
The answer to the student's question is b. Incremental backup.