oil and coal wind and wood nuclear and geothermal hydropower and natural gas
I gave my students this multiple choice question: Photovoltaic cells capture photons of sunlight and transform them directly into electricity. Many of Earth's other energy resources are simply transformed solar energy. Which two energy resources store energy that did not begin as solar energy?

Only one answer is correct among these 4 choices:
- oil and coal
- wind and wood
- nuclear and geothermal
- hydropower and natural gas

Could you tell me which one is correct?

nuclear and geothermal