Question: Upon detecting a format error in an RP-DATA message, how should the SMR (Short Message Relay) entity respond, according to specifications for Point-to-Point Short Message Service (SMS) on mobile radio interfaces?
Option 1: Return an RP-ERROR message with a cause value and possibly extended diagnostic information, then release or abort the CM-connection, entering the Idle state.
Option 2: Ignore the error and continue attempting to process the RP-DATA message to ensure message delivery.
Option 3: Send a request for retransmission of the RP-DATA message without notifying the originator of the error.
Option 4: Immediately enter the Idle state without sending any response or notification regarding the format error.
Explanation: This is the correct response because detecting a format error in an RP-DATA message should trigger specific error handling. This includes notifying the other party with an RP-ERROR message (providing cause and possibly diagnostic information), followed by releasing or aborting the CM-connection, and then transitioning into the Idle state to maintain network integrity and efficient resource management.