Which three statements are true about Data Guard configurations? 

Answer options:

A. All databases in one Data Guard environment must have the same database name.
B. VALID_FOR is a LOG_ARCHIVE_DEST_N attribute that enables DB role change operations without having to modify LOG_ARCHIVE_DEST_n when performing switchovers or failovers.
C. For Standard Edition, LOG_ARCHIVE_DUPLEX_DEST is used to configure redo transport, from the primary to the standby database.
D. When using the Data Guard Broker, an spfile is not required.
E. Up to 30 physical standby databases may exist within one configuration.
F. The Oracle recommendation for the number of standby redo log groups per thread is one more than the number of online redo log groups per thread.

AEF

A: Parameter DB_NAME - On a primary database, specify the name used when the database was created. On a physical standby database, use the DB_NAME of the primary database. E: A Data Guard configuration includes a production database referred to as the primary database, and up to 30 directly connected replicas referred to as standby databases. F: The Far Sync instances standby redo logs (SRLs) should have the same number of redo log groups as on the primary +1 for each thread as per standard MAA Best Practices. Incorrect: not D: You must use a server parameter file (SPFILE) to ensure the broker can persistently reconcile values between broker properties and any related initialization parameter values. References: https://docs.oracle.com/database/121/SBYDB/create_ps.htm#SBYDB4720 https://docs.oracle.com/database/121/DGBKR/install.htm#DGBKR090