Why are light-years used to measure distances in space?

Question

A. The speed of light is slower in space.
B. The speed of light is faster in time.
C. Distances in space constantly change.
D. Distances between stars are very large.

I think it's C. Check my answer somebody plz??

Answer 1

C is not right. B is not right. The correct answer is D.

Answer 2

Thanks!!