Which two actions would you recommend in this scenario?

You require multiple groups of DBAs to administer different databases on the same server. Which two actions would you recommend in this scenario? (Choose two.)

A.
Run Oracle Universal Installer (OUI) as the user root.

B.
Create a separate OSDBA group for each set of databases.

C.
Create database instances in separate ORACLE_HOME directories.

D.
Create a separate OPER group and make it the primary group for the administrators.