You set the recovery window to seven days and the backup optimization to ON using the CONFIGURE command of Recovery Manager （RMAN）. The most recent backup of the TOOLS tablespace to disk was taken on January 3. The TOOLS tablespace is read­only. 
On February 21， when you execute a command to back up all the tablespaces to disk， you find that RMAN backs up the TOOLS tablespace also， even though the contents of the tablespace have not changed after the backup on January 3. 
Because there are no changes made to the TOOLS tablespace， you decide that the tablespace should not be backed up by RMAN. What can you to do skip backing up the TOOLS tablespace without changing the current backup optimization setting？（）

You defined the Recovery Manager （RMAN） retention policy to recovery window of 7 days by executing the following command： 
RMAN> CONFIGURE RETENTION POLICY TO RECOVERY WINDOW OF 7 DAYS; 
When a backup is performed， what would be the status of this backup after seven days？（）