During practice, a baseball player hits a very high fly ball, and then runs in a straight line and catches it. Which had the greatest displacement during the time period from the hitting of the ball to its catching

The player and the ball have the same displacement

Explanation:

Displacement is the distance between the final position and initial position, When the ball is hit upwards, it is caught at the same height. The vertical displacement of the ball is zero. The horizontal displacement of the ball would be equal to the displacement of the player because the player runs in a straight line to catch the ball.