The only energy source which is not in any way related to the Sun is

Correct option is D

Geothermal energy is derived from the Earth’s internal heat, which is generated primarily by the decay of radioactive materials deep inside the Earth. Unlike hydro, tidal, and wind energy, which are either directly or indirectly driven by solar processes (e.g., sunlight affects weather patterns and ocean currents), geothermal energy is not related to the Sun.
Information Booster:
Hydro – Solar energy drives the water cycle, which powers hydroelectricity.
Tidal – Though mainly driven by the moon’s gravitational pull, solar influences affect tidal movements.
Wind – Atmospheric heating by the Sun causes air movement, creating wind energy.