Why Do Astronomers Need Special Units, in Addition to the Metric

Multiple Choice

Why do astronomers need special units, in addition to the metric system of units such as meters and kilograms, to describe the universe?

A) Distances and masses are very large, and representing them in metric units is cumbersome.
B) Metric units cannot represent correctly the curvature of space observed by astronomers.
C) Units used in the metric system are known to be insufficiently accurate to satisfy the precision needed in modern astronomy.
D) Metric units are too large to represent astronomical quantities with sufficient precision.