A.when multiple databases are to be registered with the listener
B.when DBAs need to connect remotely to start up the database instance
C.when users need to connect the database instance using the host naming method
D.when the database instance that is to be registered with the listener is configured in shared server mode

A.The ORCL instance is registered dynamically with the listener.
B.The ORCL instance is registered statically in the listener.ora file.
C.The number of current client connections handled by the service handler is two.
D.The total number of client connections handled so far by the service handler is two.