College Physics (4th Edition)

The correct answer is: (e) $I$ and $K_{rot}$ only
No external torque acts on the diver, so the angular momentum $L$ remains constant. More of the mass is brought closer to the axis of rotation. This decreases the rotational inertia $I$ Since positive work was done by the diver to pull the legs inward, the system gains energy. Therefore, the rotational kinetic energy $K_{rot}$ increases. The correct answer is: (e) $I$ and $K_{rot}$ only