which database operation would you need the database to be in the MOUNT state?

For which database operation would you need the database to be in the MOUNT state?

A.
Re-creating the control files

B.
Renaming the control files

C.
Dropping a tablespace in your database

D.
Dropping a user in your database

E.
Configuring the database instance to operate in the ARCHIVELOG or NOARCHIVELOG modes