Question: Upon receiving a release request from Short Message Relay Layer (SM-RL) while in the Wait for CP-ACK state, what action does the Short Message Control (SMC) entity take if it subsequently enters the Idle state?
Option 1: Sends an MM-connection release request to the MM-sublayer.
Option 2: Enters the MM Connection Established state to process the request.
Option 3: Discards the stored release request from SM-RL.
Option 4: Transitions back to the Wait for CP-ACK state to await further instructions.
Explanation: According to the described behavior, if the SMC entity in the Wait for CP-ACK state receives a release request from SM-RL and then enters the Idle state (instead of MM Connection Established), it discards the stored release request. This highlights the importance of state transitions in managing Short Message Service (SMS) connections over mobile radio interfaces, ensuring resources are efficiently allocated or released based on the current operational state.