When an ATS or apron-management unit controls pushback on a congested apron, what should its authorization accomplish?

1. Coordinate the maneuver under the local apron procedure so it does not conflict with known traffic, and specify any required direction, restriction, or sequence clearly.
2. Authorize pushback without checking apron taxi traffic.
3. Board the aircraft to assist with passenger seatbelts.
4. Instruct the ground tug driver to drive at 50 km/h.