The correct option is B Newton's second law of motion
(a) A fast moving ball has a tendency to keep moving due to inertia. According to Newton's second law, the force with which ball is moving is equal to its mass multiplied by its acceleration. When we catch a ball, momentum of the ball is transferred from ball to hand. If we keep our hand stationary, the force with which momentum is transferred might hurt our hand. But as soon as we pull our hands back, net momentum is decreased, thus reducing the force with which ball makes an impact with our hands.