When does Backup Exec Data Lifecycle Management (DLM) delete all the backup sets on which the backup set expiry date is reached?
A. when the backup sets contain multiple unexpired incremental backup sets, but the full backup has expired
B. when the backup sets contain expired backup sets created by different backup definitions
C. when the Allow Backup Exec to delete all expired backup sets option is checked
D. when the overwrite protection level is set to None