Which two options do you have for performing usermanaged backups?

You are working on a database that must be functioning 24 hours a day, 7 days a week.
The database is configured in ARCHIVELOG mode. Which two options do you have for
performing usermanaged backups? (Choose two.)

A.
You can perform consistent backups only.

B.
You can back up only those data files whose headers are frozen by using ALTER
TABLESPACE BEGIN BACKUP or ALTER DATABASE BEGIN BACKUP commands.

C.
You can perform a complete database backup without shutting down the database
instance.

D.
You can back up data files only when all data files have the same SCN recorded in
the control file.