Which two Data Guard features require the use of flashb…

Which two Data Guard features require the use of flashback database by the broker?

A.
Read-Mostly physical standby implementations

B.
Far Sync Instances

C.
Fast-Start Failover

D.
Real Time Query

E.
Snapshot Standby databases

Explanation:
C: Prerequisites that must be met before the broker allows you to enable fast-start failover include: Enable
Flashback Database and set up a fast recovery area on both the primary database and the target standby
database.
E: Introduced in 11g, snapshot standby allows the standby database to be opened in read-write mode. When
switched back into standby mode, all changes made whilst in read-write mode are lost. This is achieved using
flashback database, but the standby database does not need to have flashback database explicitly enabled to
take advantage of this feature, thought it works just the same if it is.
https://docs.oracle.com/database/121/DGBKR/sofo.htm#DGBKR391
https://oracle-base.com/articles/12c/data-guard-setup-using-broker-12cr1#flashback_database