Which of the following statements is not correct regarding media servers deployed with Cisco Unified Customer Voice Portal?

Which of the following statements is not correct regarding media servers deployed with Cisco Unified Customer Voice Portal?

A.
To provide redundancy, multiple media servers can be deployed using a gatekeeper (H.323 deployments) or a proxy server (SIP deployments).

B.
Media servers can provide prerecorded audio files, ASR grammars, or external VXML documents to the VXML gateway.

C.
The media server is an optional component, because audio files can be stored in local flash memory on the VXML gateway.

D.
If ASR or TTS is being used, prompt audio files must be recorded as G.711.