If $t_1$ and $t_2$ are the times of flight of two particles having the same velocity $u$ and range $R$ on the horizontal, then $t^2_1 + t^2_2$ is equal to

Question

( A ) $\frac{u^2}{g^2}$
( B ) $\frac{4u^2}{g^2}$
( C ) 1
( D ) $\frac{u^2}{2g^2}$