Micobranzuela2007go Micobranzuela2007go Science Answered 13. In a cup of liquid water, when would the water molecules stop moving? A. The molecules would stop moving if the liquid water in the cup became a solid. B. The molecules would stop moving if the liquid in the cup became a gas. C. The molecules would stop moving if the liquid water in the cup became stillD. The molecules would not stop moving in the cup of liquid water.