I believe the answer is B. I say Natural gas because the materials used for the natural gas can run out. Renewable energy sources are sources of energy that are continuous and do not run out. Biomass is gotten from waste of living things, as long as there are living things, it lasts. The wind keeps coming, so it provides more energy. Geothermal energy is the energy generated and stored in the earth. There will always be heat on earth. Hope i helped. Have a nice day. Happy new year.
