Question: What action does the MME take when it receives an ESM DATA TRANSPORT message from a UE located in an area where the PLMN is not permitted to operate?
Option 1: The MME forwards the message to the Serving Gateway.
Option 2: The MME discards the message.
Option 3: The MME sends a reject message to the UE.
Option 4: The MME initiates a location update procedure.
Explanation: When the MME determines that the UE is in a location where the PLMN is not allowed to operate, it discards the ESM DATA TRANSPORT message. This ensures that the network does not process any data from the UE in an unauthorized area, maintaining compliance with regulatory requirements and preventing potential security breaches.