Your Data Guard environment has two remote physical standby databases. Client applications use the local naming method to connect to the primary database instance. You want applications to automatically connect to the new primary database instance in case of a switchover or a failover. Which will fulfill this requirement? 

Answer options:

A. Create a database service on each standby database that is started automatically by a trigger, when the database role is PRIMARY; modify the connection descriptors used by client applications to include all the standby hosts and connect to the database instance using that service name.
B. Create a database service on the primary database that is started automatically by a trigger, when the database role is PRIMARY; modify the connection descriptors used by client applications to include all the standby hosts and connect to the database instance using that service name.
C. Set the INSTANCE_NAME parameter identically on all databases; modify the connection descriptor on client applications to include all the standby hosts and connect to the database instance using that service name.
D. Set the DB_NAME and DB_UNIQUE_NAME identically on all databases; modify the connection descriptors on client applications to include all the standby

A

References: http://docs.oracle.com/cd/B19306_01/server.102/b14239/scenarios.htm#i1054744