Which of the following would be the most appropriate title for the passage? A. Energy from Water Sources: The Feasibility of Commercial Systems B. Geothermal Energy Retrieval: Volcanic Activity and Hot Dry Rocks C. Energy Underground: Geothermal Sources Give Way to Fossil Fuels D. Tappable Energy for America's Future: Hot Dry Rocks E. High Geothermal Gradients in the United States: Myth or Reality?