Question: What action does the SMF take when it receives a PDU SESSION RELEASE REQUEST message but does not accept the request to release the PDU session?
Option 1: The SMF sends a PDU SESSION RELEASE ACCEPT message.
Option 2: The SMF creates and sends a PDU SESSION RELEASE REJECT message with a specific 5GSM cause IE.
Option 3: The SMF ignores the PDU SESSION RELEASE REQUEST message and takes no further action.
Option 4: The SMF sends a PDU SESSION RELEASE REQUEST message back to the UE.
Explanation: According to the specified procedure, when the SMF does not accept the request to release the PDU session, it creates a PDU SESSION RELEASE REJECT message and sets the 5GSM cause IE to indicate the reason for rejecting the PDU session release. This ensures that the UE is informed of the rejection and can take appropriate actions accordingly.