The idea that is most prominently included in the U.S. Constitution from the Enlightenment is Montesquieu’s ideas about separation of powers. Montesquieu advocated for dividing government power into distinct branches to prevent any one branch from becoming too powerful, which significantly influenced the structure of the U.S. government as established in the Constitution.
While other Enlightenment thinkers like Hobbes (who focused on the social contract) and Voltaire (who emphasized civil liberties) contributed to the broader philosophical landscape, it is Montesquieu's concept of separation of powers that is directly reflected in the Constitution. The idea of "no taxation without representation" is often associated with the American Revolution and Patrick Henry but is not a specific Enlightenment principle foundational to the Constitution itself.
Therefore, the correct response is: Montesquieu’s ideas about separation of power are included.