the Moon to revolve around Earth. Earth to revolve around the Sun. Earth to rotate on its axis. the Sun to rotate on its axis.
I gave my students this multiple choice question: The length of a year is determined by the amount of time it takes

Only one answer is correct among these 4 choices:
- the Moon to revolve around Earth.
- Earth to revolve around the Sun.
- Earth to rotate on its axis.
- the Sun to rotate on its axis.

Could you tell me which one is correct?

Earth to revolve around the Sun.