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.<br /> Which statement about performing user-managed backups in a 24x7 environment is true?()
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