Answer:
The driveway pushing up on the car
Step-by-step explanation:
A reaction force is the force that acts upward on an object resting on a particular surface to balance the effect of the weight of the object which acts downward. For this 2-ton car parked on a driveway, the reaction from the floor of the driveway acts upward on the car to balance the downward force of the weight of the car since in every action, there is equal and opposite reaction. By this force balancing, the car will neither move up nor sink down to the ground as long as it is parked on the driveway.