​A rainbow is formed by water droplets suspended in the atmosphere after the rain shower. The phenomenon responsible for occurring of rainbow consists of:​​

Correct option is D

The correct answer is (D) A combination of refraction, scattering and dispersion.

The phenomenon responsible for the formation of a rainbow consists of dispersion, reflection, and refraction of light in water droplets. Here's how each process contributes:

1. Refraction: When sunlight enters a water droplet, it slows down and bends due to the change in medium from air to water (this is called refraction). The amount of bending depends on the wavelength (color) of the light, with shorter wavelengths (blue and violet) bending more than longer wavelengths (red).
2. Reflection: After the light refracts into the droplet, it reflects off the inner surface of the droplet. This internal reflection causes the light to travel back through the droplet.
3. Dispersion: As the light exits the droplet, it refracts again, and the different wavelengths (colors) spread out, creating the spectrum of colors we see as a rainbow. Each color bends by a different amount, leading to the separation of colors.
4. Refraction (again): Finally, the light exits the droplet and bends again as it moves from water back into the air, further spreading the colors.

These combined processes (refraction, reflection, and dispersion) result in the formation of a rainbow, with the colors arranged in a circular arc in the sky.