Final answer:
James Madison advocated for the separation of powers by equally distributing power among the three branches of government, ensuring none would dominate through a system of checks and balances. Hence, the answer is (a) By equal power distribution.
Step-by-step explanation:
James Madison believed that the necessary separation of powers among the three branches of the United States government should be achieved through a system of checks and balances. Each branch would have its own distinct powers but also some control over the other branches, ensuring that no single branch could dominate. This concept is a fundamental principle in the design of the U.S. Constitution and guided the Founding Fathers in creating a government structure where the executive, legislative, and judiciary would balance each other. Therefore, the answer to the question would be (a) By equal power distribution, as Madison emphasized the importance of distributing power equally to prevent one branch from becoming too powerful over the others.