Question: When does an MS deactivate mobility management for IMS voice termination?
Option 1: When the MS is enabled for mobility management for IMS voice termination.
Option 2: When at least one of the two parameters voice domain preference for UTRAN and voice domain preference for E-UTRAN is "CS voice only".
Option 3: When the MS's availability for voice calls in the IMS changes from "available" to "not available".
Option 4: When the IMS voice over PS session indicator received has the value - "IMS voice over PS session not supported in Iu mode and A/Gb mode".
Explanation: The MS deactivates mobility management for IMS voice termination when its availability for voice calls in the IMS changes from "available" to "not available". This is a specific condition that triggers the deactivation of mobility management, ensuring efficient resource allocation and call handling.