Why is the sky orange and red at sunrise and sunset?

At sunrise and sunset, sunlight travels through a thicker layer of atmosphere before reaching you. Air molecules scatter shorter blue wavelengths more strongly, so more of that light is scattered away from your direct view while longer orange and red wavelengths pass through. That is why choice C, “The thick atmosphere scatters all but longer wavelengths,” is the best answer; the colors are scattered, not absorbed as choice B suggests.

AI-written and checked against the verified answer.