Concept:A unitary system works best where people share similar culture, language, and values.Explanation:In a unitary system, the central government holds most power. Such a system is easily adopted when the state is homogeneous. Homogeneity means the citizens have common traditions, language, and identity. This unity reduces the need for separate regional governments. The other options are not direct reasons for adopting a unitary system.Answer:A. of homogeneity