A block of mass m takes time t to slide down on a smooth inclined plane of angle of inclination `theta` and height h. If same block slids down on a rough inclined plane of same angle of inclination and same height and takes time n times of initial value, then coefficient friction between block and inclined plane is

Options

A. `[1+n^(2)]tan theta`
B. `[1-(1)/(n^(2))]tan theta`
C. `[1-n^(2)]tan theta`
D. `[1+(1)/(n^(2))]tan theta`