If you were writing a report about "Potential Future Applications of Geothermal Energy," which of the following would be the MOST relevant topic to include?
A) The history of coal mining in the 19th century.
B) The impact of ocean tides on marine ecosystems.
C) Innovative ways to extract heat from deep within the Earth's crust.
D) The design of advanced nuclear fission reactors.
E) The role of biofuels in the aviation industry.