Answer: The answer will be A
Explanation:
There is acceleration in all cases velocity changes. In options b and c the speed is constant, then there is no acceleration. In option a, the car was moving and then stop, therefore, its speed decrease to zero, and that represent an acceleration.
On a roller coaster potential energy builds up while you are going up a hill . Once at the top all of that energy is being released this giving you a push which means all of that energy is making you down down the hill. Hope this helps you.
They move in a waves motion