Which source of power cannot be traced back to the sun's energy?

The correct answer is lunar tidal energy because it is primarily derived from the gravitational forces exerted by the moon and, to a lesser extent, the sun. While the moon's gravitational pull creates tides on Earth, this energy source does not directly rely on solar energy. In contrast, geothermal energy is associated with the Earth's internal heat, wind energy results from atmospheric movements influenced by solar heating, and solar energy, as the name implies, comes directly from the sun. Therefore, lunar tidal energy stands apart as it does not trace its origin back to solar energy but rather to the gravitational interaction with the moon.