Concept:Equilibrium depends on whether a displaced ball returns, moves away, or stays in its new position.
Explanation:For position A, a slight displacement causes the ball to continue moving away from its starting point.
This is unstable equilibrium.
For position B, a slight displacement makes the ball return to its original position.
This is stable equilibrium.
For position C, a slight displacement leaves the ball at its new position without returning or moving further.
This is neutral equilibrium.
Answer:A is unstable, B is stable, and C is neutral.
Therefore, the correct option is D.
