The correct answer is B. The sun.
Explanation
The sun is responsible for the air of the earth's surface having different temperatures because the sun's rays penetrate the earth's surface with different angles, for example, in the middle zones the rays enter directly, while in the polar zones the rays enter with less intensity through the angle into which the atmosphere penetrates. Besides this, these rays and especially the ultraviolet radiation leads to differences in the Earth atmosphere that made the termosphere have the highest temperature due to ultraviolet radiation while the temperature decreases in other layers. So, the correct anwer is B. The sun.
