The correct answer is A. The Social Contract.
Explanation
Rousseau (1712 - 1778) was a Swiss philosopher of the Enlightenment who stood out for influencing the French Revolution with his ideas about government; among his most outstanding books is the Social Contract, in which he expresses his ideas about government, the State, society, freedom and the individual. One of the most important ideas expressed in this book is the importance of the individual will because Rousseau states that it is through the will of the individual, who gives part of their freedom, a State is formed and the peaceful and safe coexistence between the individuals is guaranteed. So, the correct answer is A. The Social Contract.
