Answer
See the figure below.
Work Step by Step
The ball starts from rest and then moves under the free-fall acceleration until it hits the ground. Then, the ground pushes the ball upward so the ball bounces back due to the force exerted by the ground upward which means that at the time of contact between the ball and the ground the ball's acceleration points upward.
After that, the ball moves upward again under the free-fall acceleration until it stops before it falls back again.
See the figure below.
