At the top, the roller coaster has a very large amount of potential energy. This amount of potential energy is present because the roller coaster is at a elevated place with respect to the ground. While the roller coaster goes down some of the potential energy is lost depending on the change in height and is converted to other energy. As the roller coaster is losing the potential energy, it gains some kinetic energy since this type of energy is dependent on the speed of the object moving and the mass. Thus the answer is b where potential energy is converted to kinetic energy.
