Which option is correct?what is the difference between A and C??

(a)  The scattering of light is inversely proportional to the fourth power of wavelength.that the shorter wavelength scatters more and our eye is more sensitive to blue colour. So the sky appears blue.

(b) We observe the sun red at the time of sunrise and sunset because the Red colour is least scattered. During the time of sunset and sunrise, the distance between the sun and earth is high. So by the time light reaches the surface of the earth all the colours except red get scattered away.

option A is correct