What type of backup involves copying all files that have been changed since the last full backup?

A.  Full Backup

B.  Differential Backup

C.  Incremental Backup

D.  Mirror Backup

Correct Answer:  B

Explanation:

In the context of data backup strategies, different types of backups serve different needs. Here's a breakdown of each option:

Full Backup: This involves making a copy of all system files and data at a particular point in time. It provides the highest level of protection, but it's also the most time-consuming and requires the most storage space.

Differential Backup: This type of backup copies all files that have changed since the last full backup. Each new differential backup will contain all the changes since the last full backup, even if some of those files were included in previous differential backups.

Incremental Backup: This backs up only the files that have changed since the last backup, whether that last backup was a full backup or an incremental backup. Incremental backups save time and storage space, but restoring from them can be slower because you need all the previous incremental backups plus the full backup.

Mirror Backup: This creates an exact mirror or replica of the source data. It's not really designed to store changes made since the last backup but to provide a one-to-one mirror of the current state.