Concept:A unicameral legislature is a law-making body that has only one chamber or house.Explanation:In a unitary system of government, the central government holds supreme power.Such a system often adopts a unicameral legislature because there is no need for a second chamber to represent regional or state interests.Most countries with a unitary system of government use one legislative chamber.In contrast, federal systems usually have bicameral legislatures to represent both the people and the component states.Unicameralism is therefore more popular and practical in unitary states where political authority is concentrated centrally.Answer:A. unitary system