If the velocity of projection is u m/sec and the angle of projection is. $$\alpha^\circ$$, the maximum height of the projectile on a horizontal plane is

A

$$\frac{u^2 \sin^2 \alpha}{2g}$$

B

$$\frac{u^2 \cos^2 \alpha}{2g}$$

C

$$\frac{u^2 \tan^2 \alpha}{2g}$$

D

$$\frac{u^2 \sin^2 \alpha}{g}$$