the rate at which the universe is expanding the distance between stars in the Milky Way the time it takes for planets to complete their orbits the speed at which light travels through the universe
I am hesitating between 4 options to answer the following question, which option should I choose?
Question: Which measurement is best expressed in light-years?
Possibilities:
- the rate at which the universe is expanding
- the distance between stars in the Milky Way
- the time it takes for planets to complete their orbits
- the speed at which light travels through the universe

the distance between stars in the Milky Way