Which one has the greater kinetic energy (KE)?

The correct answer to this question is A. The bowling ball has more kinetic energy because it has a greater mass than the ping pong ball and greater distribution of mass. A ping pong ball is hollow, whereas the bowling ball's solid mass affects the inertia as it rolls.

Had the bowling ball and the ping pong ball been dropped from the same height, at the same time, with the exact same force, they would hit the ground at the same time. However, when there is a slope involved, the mass and mass distribution of the balls impacts the outcome.