Which SIP Profile configuration element is necessary for the Cisco Unified Communications Manager to send acknowledgement of provisional responses?

Refer to the exhibit.

A user reports that when they call a specific phone number, no one answers the call, but when they call from a mobile phone, the call is answered. The engineer troubleshooting the issue is expecting the far-end gateway to cut through audio on the 183 Session Progress SIP message .

Which SIP Profile configuration element is necessary for the Cisco Unified Communications Manager to send acknowledgement of provisional responses?
A . Allow Passthrough of Configured Line Device Caller Information must be enabled.
B . Accept Audio Codec Preferences in Received Offer must be set to On.
C . On the SIP Profile, the configuration parameter SIP Rel1XX Options must be set to Send PRACK for all 1xx Messages.
D . Early Offer for G Clear Calls must be enabled.

View Answer

Answer: C