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.
