Question: When a mobile network has provisioned Calling Line Identification Presentation (CLIP) for a subscriber, and the User Equipment (UE) supports displaying line identification, what should the UE do upon receiving a Mobile Terminating (MT) call if the calling line identity is not available?
Option 1: Automatically reject the incoming MT call due to unavailable line identity.
Option 2: Display the reason why the line identity is not available, as indicated by the Presentation Indicator.
Option 3: Always display the last known calling line identity from previous calls.
Option 4: Silence the incoming call notification without any visual cue.
Explanation: According to telecom standards for User Equipment (UE) behavior, when Calling Line Identification Presentation (CLIP) is provisioned but the line identity is not available for a Mobile Terminating (MT) call, the UE should prioritize transparency. Displaying the reason for the unavailability informs the user about the status of the caller's information, enhancing user experience and clarity.