The distance is extremely large. The distance is a rough estimate. Only light can travel between stars. Light signals were timed reflecting from the star.
I gave my students this multiple choice question: The nearest star to the Sun is described as being 4.3 light-years away. Which statement explains why the light-year unit of measure is used in this description?

Only one answer is correct among these 4 choices:
- The distance is extremely large.
- The distance is a rough estimate.
- Only light can travel between stars.
- Light signals were timed reflecting from the star.

Could you tell me which one is correct?

The distance is extremely large.