Before performing a mksysb system backup, which of the following procedures should a system administrator perform to avoid backing up certain user files?（）

• A、Add the list of files to /etc/exclude.rootvg.
• B、Modify the image.data file and add the files to be excluded form the backup.
• C、Modify the bosinst.data file and specify which files are to be excluded from the backup.
• D、Specify the files to be excluded on the command line when executing the mksysb command.