Which of the following backup techniques is MOST likely to require the LEAST amount of data transfer during each backup cycle?

File incremental backups copy entire files that have changed since the last backup, which can include many unchanged blocks within those files.

Block incremental backups only copy the data blocks that have changed since the last backup (either full or incremental), resulting in the smallest amount of data transfer during each backup cycle. This method is highly efficient because it identifies and transfers only the granular block-level changes within files.

File differential backups copy entire files that have changed since the last full backup, typically transferring more data than incremental backups over time.

Block differential backups copy all changed blocks since the last full backup, which will generally transfer more data than block incremental backups over multiple cycles.