Question: In SRVCC or 5G-SRVCC handover from NG-RAN to UTRAN, when does the mobile station attach the user connection if prior to SRVCC the MS in the PS domain was receiving media for the session subjected to handover?
Option 1: When the call control entity enters the "call delivered" state.
Option 2: When the call control entity enters the "mobile originating call proceeding" state.
Option 3: When the call control entity enters the "active" state or the "call received" state.
Option 4: When the call control entity enters the "hold" state.
Explanation: According to the specification, for SRVCC handover or 5G-SRVCC handover from NG-RAN to UTRAN, the mobile station attaches the user connection when the call control entity enters the "call delivered" state if prior to SRVCC the MS in the PS domain was receiving media for the session subjected to handover. This allows the network to provide in-band tones and announcements to the UE.