A projectile can have the same range R for two angles of projection. If $t_1$ and $t_2$ be the times of flights in the two cases, then the product of the two times of flights is proportional to :

Question

( A ) $\frac{1}{R^2}$
( B ) $\frac{1}{R}$
( C ) $R$
( D ) $R^2$