Which backup method does not change the archive bit?

The correct answer is that the differential backup method does not change the archive bit. The archive bit is a file attribute used by backup software to determine which files have been modified since the last backup.

In a differential backup, all files that have changed since the last full backup are included in the backup set. Importantly, this method does not alter the archive bit of the files that are backed up. Thus, the system can accurately determine which files need to be backed up in subsequent differential backups as they will still retain their archive status until a full backup is performed.

This approach provides a way to back up data without resetting the archive status of individual files. When a full backup is completed, the archive bit for those files is reset. Incremental backups, on the other hand, do change the archive bit to indicate that the files have been backed up, leading to potential complications in identifying files that still require backups in the future. Selective backups are more of an ad-hoc type of backup rather than a standardized method, so comparing their effects on the archive bit is not as straightforward.