central and state governments influence each other in\na unitary system.\na federal system.\na confederal…

Brief Explanations:

In a federal system, power is divided between central and state - level governments, and they interact and influence each other. In a unitary system, the central government has more control over states. In a confederal system, states have more power than the central authority. A democratic system is about how people participate in governance and not specifically about the relationship between central and state governments in terms of influence.

Answer:

B. a federal system