A ball rolls off top of a staircase with a horizontal velocity `u m s^-1`. If the steps are `h` metre high and `b` mere wide, the ball will just hit the edge of `n th` step. Find the value of `n`.
A. `n=(gx^(@))/(2hu^(2))`
B. `n=(2hu^(2))/(gw^(2))`
C. `n=(2u^(2))/(gw^(2)h)`
D. `n=(2hw^(2)u^(2))/(g)`