Question: What action can the MME take upon receiving a SERVICE REQUEST, EXTENDED SERVICE REQUEST, or CONTROL PLANE SERVICE REQUEST message?
Option 1: The MME will ignore the message and wait for further instructions.
Option 2: The MME will send an error response to the UE.
Option 3: The MME will initiate a dedicated bearer activation procedure.
Option 4: The MME may initiate EMM common procedures, such as authentication or security mode control.
Explanation: Upon receiving specific request messages from the User Equipment (UE), the Mobility Management Entity (MME) has the capability to trigger certain essential processes. These include authentication to verify the UE's identity and security mode control to ensure secure communication. This action is crucial for maintaining network integrity and ensuring that only authorized UEs access the network resources.