tilt of the Earth. tilt of the Moon. revolution of the Earth around the Sun. revolution of the Moon around the Earth.
I gave my students this multiple choice question: The phases of the Moon are caused by the

Only one answer is correct among these 4 choices:
- tilt of the Earth.
- tilt of the Moon.
- revolution of the Earth around the Sun.
- revolution of the Moon around the Earth.

Could you tell me which one is correct?

revolution of the Moon around the Earth.