Concept:Natural sources of light emit their own light without any human involvement.Explanation:The Sun produces its own light by nuclear fusion, so it is a natural source of light.A glow worm also produces its own light through a chemical reaction called bioluminescence, so it is a natural source.The Moon does not produce its own light; it merely reflects sunlight.Therefore, only II (Sun) and III (Glow Worm) are natural sources of light.Answer:C. II and III only