A school bus is stopped on a two-lane, undivided road with its red lights flashing and stop arm extended. A vehicle is approaching from the opposite direction. What is the vehicle legally required to do?

1. Slow down to 10 mph and pass the bus with caution.
2. Stop at least 20 feet away from the bus and wait.
3. Proceed without stopping as they are in the opposing lane.
4. Honk to alert any children and then pass the bus.