You issued the following command to mount the DATA disk group in restricted mode：   ALTER DISKGROUP data MOUNT RESTRICT；   What is the implication of this command？（）

• A、 The client RDBMS instance can access the file as a read-only file.
• B、 A new disk cannot be added to a disk group.
• C、 A disk in a disk group can be taken offline.
• D、 The client RDBMS instance cannot access the files in the disk group.