【单选题】You are working on a 24X7 database. You want to design a backup strategy for your database that uses user managed backups. You want to be able to perform all backups while the database remains online....
A.
You must have change tracking enabled in your database
B.
Your database must be running in NOARCHIVELOG mode
C.
To back up a tablespace, it must be in backup mode
D.
To back up a tablespace, it must first be taken offline