Every Sunday the Unix system administrator has a job that executes a full backup of the entire Unix system your database is on. Is this backup usable for backup and recovery of your database？（）

A.  Yes， if the database is in ARCHIVELOG mode

B.  Yes， if the database is in NOARCHIVELOG mode

C.  No， the backup is not usable in any way

D.  Only if the ENABLE_ONLINE_BACKUP parameter is set to TRUE