The correct option is C Constellation
A constellation is any of the groups of stars in the sky that seem from earth to form a pattern and have been given names. For example, "The 48 traditional Western constellations are Greek". Hence, Option C is correct. Among the rest of the options, galaxy means a system of millions or billions of stars, together with gas and dust, held together by gravitational attraction, cluster means a group of similar things or people positioned or occurring closely together, congregation means a group of people assembled for religious worship. These options do not express this meaning, hence incorrect.