Correct Answer: Scattering of light

Solution : The correct option is Scattering of light.

Rayleigh scattering is responsible for the blue colour of the sky. Sunlight is made up of several colours of light with distinct wavelengths. When sunlight penetrates the Earth's atmosphere, the shorter wavelengths, mainly blue and violet, are dispersed in all directions by microscopic particles and molecules. Because of its shorter wavelength, blue light scatters more than other colours, making it more visible in our line of sight. As a result, throughout the day, the sky seems mostly blue.