Question: What happens to the Mobile Terminal (MT) after it returns 'CONNECT' in response to a 'D' command for requesting packet domain service, if no prior PS attachment or PDP context activation was performed?
Option 1: The MT directly enters the V.250 offline data state.
Option 2: The MT initiates a voice call to the specified <called address> without activating a PDP context.
Option 3: The MT may perform PS attachment and/or PDP context activation procedures before or during PDP startup, depending on the PDP type.
Option 4: The MT immediately returns a 'NO CARRIER' final result code due to missing prior setup.
Explanation: Upon receiving a 'D' command for packet domain service and returning 'CONNECT', if PS attachment or PDP context activation hasn't been previously done, the MT will proceed with these steps as part of establishing the communication. This is because the detailed behavior after entering the online data state depends on the PDP type, which may require these setup procedures to be completed before or during the PDP startup.