Which three statements are true about Global Sequences when connected to a physical standby database with Real-Time Query enabled? 

Answer options:

A. If the CACHE option is set then the size of the cache must be at least 100.
B. Their creation requires that a LOG_ARCHIVE_DEST_n parameter be defined in the standby that points back to their primary.
C. Their usage will always have a performance impact on the primary database.
D. Their usage may have a performance impact on the physical standby database if the CACHE size is too small
E. They must have the NOORDER and CACHE options set.

BDE

B: the terminal standby should have a LOG_ARCHIVE_DEST_n parameter defined that points back to the primary. D: Because the standby`s requests for a range of sequences involve a round-trip to the primary, be sure to specify a large enough value for the CACHE keyword when you create a sequence that will be used on an Oracle Active Data Guard standby. Otherwise, performance could suffer. E: In an Oracle Active Data Guard environment, sequences created by the primary database with the default CACHE and NOORDER options can be accessed from standby databases as well. References: https://docs.oracle.com/database/121/SBYDB/manage_ps.htm#SBYDB5164