In Modern Astronomy, the Constellations Are

In modern astronomy, the constellations are

A) specific patterns of stars that point to certain directions that are useful for navigation.
B) 13 specific regions of stars through which the planets and Moon appear to move in the sky.
C) a small number of well-defined and separate groups of stars in the sky.
D) 88 nonoverlapping sky regions, covering the whole sky.