What is the main characteristic of a unitary state?

A unitary state is primarily defined by its structure of governance, which is characterized by the concentration of political power and authority in a central government. In a unitary system, the central authority holds the majority of the power, and any administrative divisions or regions derive their authority from this central entity. Local governments may exist, but their powers are granted and can be revoked by the national government, making the central authority the dominant force in policy-making and governance.

This centralization allows for uniform policies and administration across the nation, which can lead to more cohesive governance. It contrasts with federal systems, where power is divided between national and regional authorities, leading to greater local autonomy. Thus, the defining feature of a unitary state is its central authority's strong control over the territory and governance, making option B the most accurate representation of a unitary state's characteristics.