A. Failed disks are taken offline immediately but are not dropped.
B. Disk data is never lost.
C. By default, the failed disk is not dropped from the disk group ever, protecting you from loss of that disk.
D. The failed disk is automatically reformatted and then resynchronized to speed up the recovery process.
E. Hot spare disks are automatically configured and added to the disk group.

A. run { open script backup_database； run script backup_database }
B. run { engage script backup_database； }
C. run { run script backup_database； }
D. Run { execute script backup_database； }
E. The name backup_database is an invalid name for an RMAN script. Trying to run it from RMAN would result in an error.