An Auto Moves at a Steady 50 Mph Down a Straight

An auto moves at a steady 50 mph down a straight level road. Which of the following is the forward drive force on the auto?

A) The backward push by the engine on the car.
B) The backward push by the drive tires on the road.
C) The drive force is actually zero in this example, because the auto is moving at a constant speed in a straight line.
D) The forward push by the road on the tires.
E) The forward push by the engine on the car.