Without seeing the diagram, I can't provide a specific answer. However, I can explain each of the options:
A. Judicial Review - This refers to the power of courts to assess whether a law is in compliance with the constitution.
B. Checks and Balances - This is a system in which the powers of government are divided among branches, each having some measure of influence over the other branches and may choose to block procedures of the other branches, which ensures that no single branch becomes too powerful.
C. Federalism - This is a system of government in which power is divided between a central authority and constituent political units (like states).
D. Direct Democracy - This allows citizens to participate directly in the decision-making process, typically through voting on specific issues rather than through elected representatives.
If you can describe the diagram or the relationships it shows, I can help you better determine which option it best represents.