The correct option is C. K.C. Wheare. Detailed Explanation:

1. Understanding Federalism: Federalism is a system of governance in which power is divided between a central authority and constituent political units (like states or provinces). This division of powers is essential for maintaining a balance between national and local interests.
2. K.C. Wheare's Contribution: K.C. Wheare, a prominent political scientist, is widely recognized for his work on federalism. His book, "Federal Government," published in 1946, is considered a foundational text in the study of federal systems. Wheare analyzed various federal systems around the world and articulated the principles that define federalism, such as the distribution of powers, the relationship between different levels of government, and the importance of a written constitution in federal arrangements.
3. Why K.C. Wheare is the Correct Answer:
4. Theoretical Framework: Wheare provided a clear theoretical framework for understanding federalism, distinguishing it from unitary systems of government. He emphasized the importance of a constitutional division of powers and the need for cooperation between different levels of government.
5. Influence on Federal Studies: His work has influenced both academic discourse and practical applications of federalism in various countries, making him a key figure in the field.

Why the Other Options are Incorrect:

• A. A. Baron de Montesquieu:
• Montesquieu was a French philosopher known for his work "The Spirit of the Laws," where he discussed the separation of powers. While his ideas influenced the development of modern political thought, he did not specifically focus on federalism as a system of governance. His contributions are more aligned with the concept of checks and balances rather than the federal structure itself.
• B. Karl Marx:
• Marx was a philosopher and economist known for his critique of capitalism and his theories on socialism and communism. His work does not center on federalism; instead, it focuses on class struggle, economic systems, and the role of the state in a capitalist society. Therefore, he is not considered a theorist of federalism.
• D. A.V. Dicey:
• A.V. Dicey was a British jurist and constitutional theorist known for his work on the British constitution and the concept of parliamentary sovereignty. While he contributed significantly to constitutional law, his focus was not on federalism. Dicey’s theories are more relevant to unitary systems and the legal framework of the UK rather than the federal structure.

Summary of Key Points:

• K.C. Wheare is recognized as a foremost theorist of federalism, particularly for his foundational text "Federal Government."
• He emphasized the constitutional division of powers and the relationship between different levels of government.
• Other theorists like Montesquieu, Marx, and Dicey, while influential in their own rights, did not specifically focus on federalism.
• Understanding the contributions of these theorists helps clarify the distinctions between federal and unitary systems of governance.

This thorough understanding of K.C. Wheare's contributions to federalism will aid in grasping the complexities of governance structures in your studies.