Aball is thrown upward and reaches a maximum height of 100m and then returns back to where it was launched. the displacement of the ball is a) 0 m b) 100 m c) 200 m d) more than 200 m

The correct answer is
A)0 m

In fact, the displacement is a vectorial quantity that corresponds to the difference between the initial and the final position of an object in motion. In this problem, the final position of the ball is equal to its initial position (because the ball returns back to where it was launched), so the displacement of the ball is zero.