Charles Louis de Secondat, lord of la Brède and baron de Montesquieu (1689 - 1755) was a French philosopher who stood out for his ideas related to the intellectual and cultural movement of the Enlightenment. His works focused on the theory of separation of powers, which has been introduced in many constitutions around the world. His most famous work on the division of powers was his treatise "On the Spirit of the Laws" in which he states that in antiquity the functions of the State (necessary for the protection of the citizen) were monopolized in a single entity, which usually associates with despotism. Therefore, he proposes to distribute public powers among different entities, which limit each other, avoiding the monopolization of power in a single person or entity. So, the correct answer is D. Baron de Montesquieu.
The three enlightened monarchs of the 18th century were: 1. Joseph II of the Holy Roman Empire 2. Catherine the Great of Russia 3. Frederick the Great of Prussia
