The sun's light is reflected by the clouds. The sun's light is refracted by the atmosphere. The sun moves from west to east each day. The sun appears to move due to Earth's rotation.
I gave my students this multiple choice question: One evening as it is getting dark, Alex sits on the front porch and watches the sun slowly disappear behind the neighbor's house across the street. Which explains this observation?

Only one answer is correct among these 4 choices:
- The sun's light is reflected by the clouds.
- The sun's light is refracted by the atmosphere.
- The sun moves from west to east each day.
- The sun appears to move due to Earth's rotation.

Could you tell me which one is correct?

The sun appears to move due to Earth's rotation.