The picture below shows a "water-wheel"-based flour mill used in olden times to grind flour: Flowing water moving water wheel to grind grains. IowaZ 2017 The process of grinding required grains to be put in between two stones. The two stones then rotated to crush the grains present in between them to produce flour. Which of the following best explains the relationship between energy and motion in the process described? (1 point) a Gravity moves the water-wheel that rotates the grinding stones b Mass of the water-wheel sets the grinding stones in motion c Moving water moves the water-wheel that rotates the grinding stones d Rotation does not need energy, as there is no motion involved