At sun rise or sun set, the sun appears to be reddish while at mid day it looks white. This is because :

[A] The sun is colder at sun rise and sun-set

[B] At sun rise or sun-set it is nearer to the earth

[C] At sun rise it is fresh and at sun-set it is about to be set

[D] Scattering due to dust particles and air molecules causes this phenomenon.

Answer & Explanation
Option: [D]