Option (c) is correct.The projectile will reach the ground after a time of 6.4 seconds.
Step-by-step explanation:
Height of cliff= 200 m
initial velocity along vertical=0
initial velocity of horizontal=200 m/s
we use the kinematic equation;
h= Vit +1/2 gt²
200=0(t) + 1/2 (9.8)t²
4.9t²=200
t²=40.82
t=6.4 seconds