Realism depicted the international politics as a struggle for power and interest, and states as unitary actors capable of rational decision making. According to all realists, basic agenda of IR are security issues, thus political and military issues are primary topics and top issues in the hierarchy among the topics of the agenda. One of the important premises of realism (particularly neo-realism) is the anarchical structure of the international system. There is no central authority to govern the relations among states. Whereas for idealists, the norms and rules which are relevant to international law and international organizations should be applied to international relations for preserving peace and order. According to realism, states are the major actors of international politics. Their interests and the rivalry for getting more powerful, shapes politics. Multinational companies (MNCs) and international organizations are not assumed as actors of international politics. The correct option is D.