What is a driver always required to do when another vehicle “sits on his tail”?

1. A Step on the brake pedal abruptly and continuously.
2. B Verify that the distance he keeps from the vehicle driving in front will allow him to brake moderately and avoid the risk of a collision from behind.
3. C You have nothing to do. The one driving behind is always found guilty in case of an accident.
4. D Accelerate immediately and increase the distance from the vehicle behind.