Question: Upon receiving an MNSMS-ABORT-REQUEST from an SMR entity, what action(s) must the CM-sublayer take to release a CM-connection in abnormal cases?
Option 1: Only send a CP-ERROR message to the peer entity without releasing lower layer services.
Option 2: Release lower layer services immediately, but only send a CP-ERROR message if explicitly requested by the SMR entity.
Option 3: Form and send a CP-ERROR message (if applicable) and then release the lower layer services.
Option 4: Ignore the request if a CP-ERROR message cannot be sent due to connection issues.
Explanation: This is the correct answer because, upon receiving an MNSMS-ABORT-REQUEST, the CM-sublayer may send a CP-ERROR message as part of releasing the connection. However, regardless of whether a CP-ERROR message is sent, the CM-sublayer must release the lower layer services to fully terminate the abnormal CM-connection, ensuring resource cleanup and proper state transition in the network.