Identify two scenarios in which the RMAN crosscheck command can be used.
A. when checking for backups that are not required as per the retention policy
B. when updating the RMAN repository if any of the archived redo log files have been deleted without using RMAN to do the deletes
C. when updating outdated information about backups that disappeared from disk or media or became corrupted and inaccessible
D. when synchronizing backups, which were not performed by using RMAN, with the RMAN repository
E. when listing backups that are required for recovery operations