The correct answer is C. Separation of church and state. In separation of powers, normally the presidential power is weaken, it has nothing to do with natural rights, and the social contract is about the way that government acts in order to make people have a high quality of life. As well as that, it is possible to say that because in many traditional societies, as was the case of Europe, many decissions were taken by the religious autorities, stopping many times the citizens' desires and corrupting many levels of politics; so that, French decided to have divided the religion and the politics making a separation church-state.
