Okay so, the least amount of potential energy translates to the most amount of kinetic energy. Potential energy is normally higher at the top, top of a roller coaster, building, etc. And so Y or W must be the answer. Y has less potential energy since it is longer. There is more time for the kinetic energy to stay as kinetic energy before reaching the top and transforming into potential energy. You could choose W but I don't think it's the right answer. Hope this helps!