Explanation

(c) When two bullets are fired simultaneously, horizontally with different speeds, then they cover different horizontal distance because there is no acceleration in this direction.
$Since,\ horizontal\ distance(R) = velocity\ \times time.$
But there is a vertical acceleration towards the earth (g), so the vertical distance covered by both bullet are
$given\ by$
$\ y = \frac{1}{2}gt^{2},\ $which is independent of initial velocity.
So, both the bullets will hit the ground simultaneously $.$