Question: Upon receiving a Floor Idle message from the floor control server interface, what actions does the floor participant interface toward the MCPTT client take if the first bit in the subtype requires acknowledgement?
Option 1: It only sends the Floor Idle message to the floor participant and enters the 'P: has no permission' state.
Option 2: It sends the Floor Idle message to the floor participant but does not store any indication regarding a Floor Ack message.
Option 3: It stores an indication for a Floor Ack message but does not send the Floor Idle message to the floor participant.
Option 4: It sends the Floor Idle message to the floor participant, stores an indication that a Floor Ack message is expected, and enters the 'P: has no permission' state.
Explanation: This correct answer reflects the precise sequence of actions outlined for the scenario where acknowledgement is required. The floor participant interface must inform the MCPTT client about the Floor Idle status, anticipate and record the need for a response (Floor Ack), and update its permission state accordingly.