A ball is bouncing down a set of stairs. The coefficient of restitution is e. The height of each step is d and the ball bounces one step at each bounce. After each bounce the ball rebounds to a height h above the next lower step. Neglect width of each step in comparison to h and assume the impacts to be effectively head on. Which of the following relation is correct ?

Options

A. `h=d/(1-e^2)`
B. `h=d/(1+e^2)`
C. `h=d/(1+e)`
D. `h=sqrtd/(1-e^2)`