Question: In the context of Mission Critical (MC) services support in Isolated Operation for Public Safety (IOPS) mode, what is the primary role of the Signalling Control Plane in relation to the Application Plane?
Option 1: To manage the radio resources for MC service transmission
Option 2: To provide direct connectivity between User Equipment (UE)
Option 3: To establish user associations and offer access/control of services for the Application Plane
Option 4: To handle media transfer for ongoing MC sessions
Explanation: The Signalling Control Plane plays a crucial role in supporting the Application Plane by managing the setup and teardown of associations between users participating in an MC service. This plane is also responsible for providing controlled access to various services across different MC services, thereby facilitating the operational integrity of the Application Plane's functions in the IOPS mode.