Which of the following is an example of an object with stored elastic potential energy? a. a wind-up toy that has been unwound b. a basketball on the ground c. a stretched rubber band d. all of the above

Let us evaluate the given answers.

A.
Because the wind-up toy has been unwound, it has no stored elastic potential energy.
This is not a correct answer.

B.
A basketball on the ground is in equilibrium. It has no stored elastic energy.
This not a correct answer.

C. 
A stretched rubber band is not in equilibrium. It has stored elastic energy that will do work (propel the rubber band) when it is released.
This is a correct answer

D.
This is not a correct answer because only C is correct.

  C