A、 When a successful backup is recorded in the RMAN repository， then a backup of the current control file is performed.
B、 When a structural change is made to the database， then a backup of the current control file is performed.
C、 When a successful backup is performed in the RMAN repository， then a backup of the spfile is performed.
D、 When a structural change is made to the database， then a backup of the alert log file will be performed.