Here's a problem to solve: The Earth's Moon is

Among the 4 following options, which is the correct answer?

- A: always much closer to the Sun than it is to the Earth
 
- B: always much closer to the Earth than it is to the Sun
 
- C: about the same distance from the Sun as it is from the Earth
 
- D: sometimes closer to the Sun than it is to the Earth and sometimes closer to the Earth than it is to the Sun
 