Which statement is true about a database in ARCHIVELOG mode?

Which statement is true about a database in ARCHIVELOG mode? (Choose the best answer)

A.
All backups taken prior to switching to ARCHIVELOG mode can be used to perform complete recovery.

B.
Online redo log files have to be multiplexed before putting the database in ARCHIVELOG mode.

C.
A Fast Recovery Area (FRA) must be configured for the database.

D.
Full database backups can be performed when the database is opened.