Answer:
(B) The balls reach the ground at the same instant.
Explanation:
Since it is a projectile motion, the time required to reach the ground is given by
t = √2h/g
Where h is the height from which the balls are thrown and g is the acceleration due to gravity.
Since both of the balls were thrown from the same height and the acceleration of both balls are also same they will reach the ground at the same instant.