how fast light travels in space. the distance light travels in one year. how large the diameters of different stars are. the time it takes the Sun to move through the galaxy.
I am hesitating between 4 options to answer the following question, which option should I choose?
Question: Scientists use the term "light year" to describe
Possibilities:
- how fast light travels in space.
- the distance light travels in one year.
- how large the diameters of different stars are.
- the time it takes the Sun to move through the galaxy.

the distance light travels in one year.