Which statement is true about active speaker?

Which statement is true about active speaker?

A.
Active speaker switching is automatic with third-party audio only.

B.
Active speaker does not work for a site without integrated audio.

C.
Active speaker switching is automatic with Cisco WebEx audio, third-party audio, and Cisco Unified MeetingPlace Release 8.5.

D.
Active speaker only works with those who have video enabled on their WebEx.