The Earth turns on its axis. The Moon turns on its axis. The Moon orbits around the Earth. Clouds cover the Moon.
I am hesitating between 4 options to answer the following question, which option should I choose?
Question: The shape of the moon appears to change regularly during each month. Which of the following best explains why the shape of the moon appears to change?
Possibilities:
- The Earth turns on its axis.
- The Moon turns on its axis.
- The Moon orbits around the Earth.
- Clouds cover the Moon.

The Moon orbits around the Earth.