Radiant energy has to do with energy from electromagnetic waves and water doesn't really have to do with that. C is out. Vibrational energy has to do with vibrating energy at different frequencies. In this case, D is also out. The stored water has to do with potential energy, because as you go up higher, there is more potential energy. Elastic potential energy has to do with an elastic object storing potential energy, while gravitational energy has to do with its height on Earth, and water is not an elastic object. It has to be gravitational potential energy, because water falls due to gravity and falls lower. The answer is B: gravitational potential energy.
