Question

8. Which of the following phenomenon is best explained by Newton's third law

of motion?
A A coin on a piece of paper remains at the same position, when the piece
of paper is removed swiftly.
B A huge rock rolls over a cliff when pushed over.
C A toy steam boat moves in water by pushing steam backward into the
water.
D A person getting off a moving bus runs for some time, before stopping.​

Answer 1

Newtons Third Law states that for every action in nature there is an equal and opposite reaction. In other words, if object A exerts a force on object B, then object B also exerts an equal and opposite force on object A.

So I think the answer you're looking for is B: A huge rock rolls over a cliff when pushed over.