the distance from earth to the north star is about 430 light years. which of the following statements describes why scientists use the light year unit to measure distances in space?

a. a light year unit is very small and distances in space are very small
b. a light year unit is very small and distances in space are very large
c. a light year unit is very large and distances in space are very small
d. a light year unit is very large and distances in space are very large