Which three steps are prerequisites for the creation of a physical standby database on a separate server using the RMAN active database duplication method? 

Answer options:

A. Set the DB_UNIQUE_NAME parameter on the primary database to a different value than that of the DB_NAME parameter.
B. Put the primary database into archivelog mode.
C. Startup nomount the standby database instance.
D. Configure Oracle Net connectivity on the primary host to the standby database instance.
E. Establish user equivalence for the database software owner between the primary host and standby host.

CDE

C: Shut down and restart the auxiliary database instance on the destination host in NOMOUNT mode. D: When a database must be accessed from another host, you must set up a password file and Oracle Net connectivity. E: When instructed to connect to the necessary instances, connect to the root as a user with SYSDBA or SYSBACKUP privilege. On both instances, the password for the user performing the duplication must be the same. References: https://docs.oracle.com/database/121/BRADV/rcmdupdb.htm