What must you do when you hear a siren coming from an emergency vehicle?

Answer: D — Stop

When you hear a siren coming from an emergency vehicle, you should immediately stop your vehicle in a safe and legal manner. This allows the emergency vehicle to pass through without any obstructions. Moving quickly to the right side or speeding up and moving to the left side of the road could potentially cause a collision with the emergency vehicle or other cars on the road. Merging to the closest lane also poses a risk as the emergency vehicle may need to use that lane to pass through. Stopping is the safest and most appropriate action to take in this situation.