Answer:
D) Separation of powers
Step-by-step explanation:
Baron de Montesquieu was an Enlightenment thinker that came up with the idea of Separation of Powers, upon which the U.S. government and many other democratic governments are based on nowadays. He proposed that in order to avoid corruption and abuses of power from the government, the power and the responsabilities of the government had to be divided into three different branches: the legislative, the executive and the judicial.
The US government is also divided into those three branches: the Legislative, which creates laws, the executive, whose main function is to enforce laws, and the judicial, which evaluates and interpret the laws.