Concept:Federalism is a system of government where power is shared between a central authority and various regional governments.
Explanation:The defining feature of federalism is the existence of two or more levels of government. One level looks after national subjects, while state or provincial governments handle local administration. Both levels enjoy independent authority in their respective areas.
Option A correctly captures this: federalism means more than one level of government exists in the country.
Option B is incorrect because a "federation of States" is not the definition; it describes how a federation can be formed.
Option C is wrong because in a federal system, state governments also have the power to make laws.
Option D is incorrect because federalism does not mean the judiciary holds the highest authority; that is a feature of judicial independence, not a definition of federalism.
Hence, only option A is correct as it directly matches the core concept of federalism.
Answer:A. existence of more than one level of government in the country.