Question: Upon detecting a 'missing mandatory information element' error in a received message, how should the receiving entity respond according to specifications for the SGs interface?
Option 1: The receiving entity should process the message as normally as possible, ignoring only the missing element.
Option 2: The receiving entity must terminate the associated session and initiate a new setup procedure.
Option 3: The receiving entity shall ignore the entire message, send an SGsAP-STATUS message with 'missing mandatory information element' cause, and include the erroneous message in the response.
Option 4: The receiving entity should log the error internally but take no immediate action regarding the problematic message.
Explanation: This is the correct procedure for handling 'missing mandatory information element' errors. By ignoring the message and returning an SGsAP-STATUS message with the specific cause and the erroneous message, the receiving entity ensures error transparency and prompts correction on the sender's side, maintaining interface protocol integrity.