Concept:A unitary system concentrates power in a single central government, and it works best in a society with shared cultural and political similarities.Explanation:A unitary system usually has one central authority that makes laws for the whole country.It is more effective in a society where people are largely alike in language, culture, and values.Such uniformity reduces regional conflicts and makes central control easier.Therefore, a homogeneous society is a key characteristic of a unitary system.Answer:B. Homogeneous society