from galaxy to galaxy from Saturn to Mercury from the Sun to Proxima Centauri from the Big Dipper to the Little Dipper
I am hesitating between 4 options to answer the following question, which option should I choose?
Question: One astronomical unit is the average distance between the Earth and the Sun. This unit is most often used to describe the distance between which two objects?
Possibilities:
- from galaxy to galaxy
- from Saturn to Mercury
- from the Sun to Proxima Centauri
- from the Big Dipper to the Little Dipper

from Saturn to Mercury