Which of the following is a natural phenomenon that shows dispersion of light?

The correct option is A Rainbow
A rainbow is a meteorological phenomenon that is caused by reflection, refraction and dispersion of light in water droplets resulting in a spectrum of light appearing in the sky. It takes the form of a multicoloured circular arc. Rainbows is formed when sunlight on passing through water droplets splits into seven colors.Splitting is due to the fact that different color light travel with different speed in water droplets.

Hence rainbow is based on dispersion of light.