The answer is Spiral. Spiral does not represent a type of nebula. There are only 3 types of nebula : Reflection, Emission & Dark. Reflection Nebulaedoes not emit its own light. Instead, it scatters the blue light from a nearby cool star. Emission Nebulae emits own light. Glow very brightly, and are frequently the birthplace of stars. Dark Nebulae also called "absorption nebulae", they block light from brighter objects behind them and can only be seen as an outline in front of a bright nebula or field of stars.
