Which two can be backed up by using RMAN in a database …

Which two can be backed up by using RMAN in a database that is in ARCHIVELOG mode?

A.
online redo log files while the database is open

B.
data files while the database is open

C.
PFILE and password file in MOUNT state

D.
data blocks in data files that have changed since the previous backup

E.
data files while the database is in NOMOUNT state

Explanation:

When you run a database in ARCHIVELOG mode, you enable the archiving of the redo log.
If you keep an archived log, you can use a backup taken while the database is open and in normal system use.
References: https://docs.oracle.com/cd/B28359_01/server.111/b28310/archredo002.htm