Explanation/Reference:
Explanation:
C: A logical standby database can be used to test new software releases and some kinds of applications on a complete and accurate copy of the primary's data. It can host other applications and additional schemas while protecting data replicated from the primary against local changes.
D: A logical standby database is open read/write while changes on the primary are being replicated.
Consequently, a logical standby database can simultaneously be used to meet many other business requirements, for example it can run reporting workloads that would problematical for the primary's throughput.
F: Logical standby can be used to greatly reduce downtime associated with applying patchsets and new software releases. A logical standby can be upgraded to the new release and then switched over to become the active primary. This allows full availability while the old primary is converted to a logical standby and the patchset is applied.
References: https://docs.oracle.com/cd/E11882_01/server.112/e41134/standby.htm#SBYDB00103