Classical and structural realism are founded on same basic principles and differ from each other at certain points such as unit of analysis to be employed, conception of balance of power, or their view related to polarity of international system. What separates essentially neorealism from the classical tradition is that it gives no account of human nature and that it disregards the statecraft ethics. However, certain elements such as the existence of independent sovereign states operating in an international system characterized by anarchy constitutes a point of departure of neorealist arguments as well. The correct answer is C.