Scattering of light: The phenomenon in which the light ray is redirected in all other directions on passing through particles of dimensions comparable to the wavelength of the light used is called scattering of light.
The white light is consists of seven colours – violet, indigo, blue, green, yellow, orange and red.
The wavelength of red colour light is maximum among all the seven constituent colours.
EXPLANATION:
During morning and evening, light has to travel the farthest than during the other parts of the day to reach our eye.
During sunset and sunrise hours, the light passing through our atmosphere to our eyes tends to be most concentrated with red light because it has maximum wavelength among all and there is almost very less scattering of red light. That’s why it looks red. Hence option 1 is correct.