Question

A constellation is _______ that forms a pattern resembling animals, mythological characters, or objects.

Answer 1

C, a group of stars that form patterns in the night sky.

Answer 2

A constellation is a group of stars.

Since human brains have evolved to look for patterns,
we sometimes seem to see patterns in groups of points. 
Different people make different pictures from the patterns ...
it depends on what they have on their mind.