Some of the objects listed following are generally considered to be single (individual) astronomical objects; others are thought of as collections of many individual astronomical objects. match these to the appropriate category.
supercluster
milky way galaxy
comet
star
planet
solar system
galaxy

supercluster - collection

Milky Way Galaxy - collection

comet - single

star - single

planet - single

solar system - collection

galaxy - collection

Explanation:

The objects in the universe can simply be divided into ones that are single objects, and ones that are a collections of numerous objects. The suprclusters, galaxies, and solar systems are collections of numerous objects, while the comets, starts, and planets are single objects.

The supercluster represents a collection of numerous galaxies, the galaxies represent gravitational bound objects such as systems of stars, stellar remnants, dark matter, dust, while the solar system is a system with central star and every objects that is influenced by its gravity.

The comets are small solar system objects, the planets are the large solar system objects, while the stars are the central and largest bodies in the solar systems.

b is the right answer for this question.