What two actions are performed as a result of this command?

Your database is in the MOUNT state and you execute the following command to open it:
ALTER DATABASE OPEN; What two actions are performed as a result of this command?
(Choose two.)

A.
The parameter file is opened.

B.
All online data files are opened.

C.
The password file is opened.

D.
All redo log files are opened

E.
All control files are opened.