The correct answer is D: the Social Contract theory.
The social contract theory means that a man's moral and political obligations are subdued to the society in which he lives, and he understands this in an unspoken contract from the moment he is born until he dies. The phrase means, in other words, that the government is formed by society and its power comes from the consent of this unspoken contract between men and society. This is the reason why this phrase illustrates the principle of the social contract theory.