Use the Figure to Answer the Next Problem

Multiple Choice

Use the figure to answer the next problem. A spring of negligible mass and spring constant k is attached to the wall on one end,and the other end is attached to the center of mass axis of a solid sphere of mass m and radius r.The spring is stretched a distance A from equilibrium and let go.The sphere rolls freely on a smooth surface.
-What is the rotational kinetic energy when the sphere is at the equilibrium position?

A)
B)
C)
D)
E) undetermined