Consider the following scenario for your database: Which statement is true regarding the backup of the TOOLS tablespace?（）

• A、The RMAN backup fails because the TOOLS tablespace is read-only
• B、The RMAN skips the backup of the tablespace because backup optimization is enabled
• C、The RMAN makes backup because optimization can be enabled only for backups to disk
• D、The RMAN makes the backup because no backup of the tablespace exists within the seven day window