Question: Under what condition does the Mobility Management Entity (MME) include the TMSI status information element in a message?
Option 1: When the User Equipment (UE) initiates a new session with a valid Temporary Mobile Subscriber Identity (TMSI).
Option 2: When the UE indicates, via an ATTACH REQUEST or TRACKING AREA UPDATING REQUEST, that no valid TMSI is available.
Option 3: During periodic location updates when the UE's TMSI has not changed.
Option 4: Upon receiving a LOCATION UPDATE ACCEPT message from the Visitor Location Register (VLR).
Explanation: This is correct because the MME includes the TMSI status information element in response to the UE signaling the absence of a valid TMSI during initial attach or tracking area update procedures, ensuring the network is aware of the UE's TMSI status for proper mobility management.