The correct answer is (b) B
Explanation:
When the ball falls in the long column of viscous liquid, it starts with zero speed and with a certain acceleration. As time passes its acceleration decreases with time.
In the speed time graph, the speed is zero at t = 0 only in graph A and B. The slope of the speed-time graph gives the acceleration. The slope of A is constant, that means the acceleration is constant which is not the case here. The slope of the graph B decreases with time i.e. the acceleration decreases with time. Thus the motion of the ball is best represented by graph B.