PASSWORD FILE AUTHENTICATION IS NECESSARY IF SYSDBA CONNECTIONS NEED TO BE MADE ACROSS A NETWORK, AND IF YOU WANT TO GRANT SYSDBA OR SYSOPER TO ANY OTHER DATABASE USERS

11. þ A and C. Password file authentication is necessary if SYSDBA connections

need to be made across a network, and if you want to grant SYSDBA or

SYSOPER to any other database users.

ý B and D. B is wrong because operating system authentication can never

be disabled. D is wrong because EXCLUSIVE doesn’t exclude users; it means

one password file per instance.