Question 464:
Which two descriptions of the characteristics of the SIP Provisional Response Acknowledgment message are true? (Choose two.)
Answer options:
A. It must be acknowledged with a "200 OK" message B. It is sent by the UAS after receiving the "Supported: PRACK" header in a previous message from the UAC.C. It is sent by the UAC after receiving the "Require: 100rel" header in a previous message from the UAS. D. It must be acknowledged with an ACK message E. It is sent by the UAC after receiving the "Require: PRACK" header in a previous message from the UAS. F. It is sent by the UAS after receiving the "Supported: 100rel" header in a previous message from the UAC.