Question: Upon receiving a Floor Release message from an MCPTT media endpoint with the first bit in the subtype set to '1', what action does the IWF floor control server take in addition to releasing resources?
Option 1: Immediately sends a Floor Taken message to all non-controlling MCPTT functions.
Option 2: Sends a Floor Ack message with the Source field set to '2' (the IWF performing the controlling role is the source).
Option 3: Enters the 'G: Idle' state without sending any additional messages.
Option 4: Stops all running timers but does not send any acknowledgement.
Explanation: According to the specifications, if a Floor Release message is received from an MCPTT media endpoint with the first bit in the subtype set to '1' (indicating acknowledgement is required), the IWF floor control server shall send a Floor Ack message. This message is specifically formatted with the Source field set to '2', indicating the IWF's controlling role, and the Message Type field set to '4' for Floor Release. This action is in addition to the general steps of releasing resources and stopping timers.