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