1. Which SIP method/message or response indicates the successful creation of a unique "dialog" between a User Agent Client (UAC) and a User Agent Server (UAS)?

A. 200 OK

B. Acknowledgment (ACK)

C. Goodbye (BYE)

D. INVITE (INV)

2. Right after a party hangs up, which sequence of SIP methods/requests or responses are exchanged between its User Agent Client (UAC) and the other party's User Agent Server?

A. INVITE - 200 OK - ACK

B. BYE - 200 OK

C. BYE - 200 OK - ACK

D. INVITE - 200 OK