To accomplish user-managed backup for the USERS tablespace, you issued the following command to put the database in backup mode:   SQL> ALTER TABLESPACE users BEGIN BACKUP;   While copying the file to the backup destination a power outage caused the instance to te minate abnormally.  Which statement is true about the next database startup and the USERS tablespace?()  
A: The database will open,and the tablespace automatically comes out of the backup mode.
B: The database will be mounted,and recovery must be performed on the USERS tablespace.
C: The database will be mounted,and data files in the USERS tablespace must be taken out of the backup mode.
D: The database will not be mounted,and you must restore all the data files for the USERS tablespace from the backup,and perform recovery.
出自:Oracle认证