Normative theories, essentially are related with the subjects of philosophy and ethic. Perpetual peace approach of Kant and European federation idea of J. J. Rousseau were interesting examples for normative studies. Value is always an important element for the background of normative studies, and such theories placed the discussion of politics in the context of morality. Here, moral factors became evident and interests were expressed through moral and ethical dimensions or in the context of values related to ideology, morality and politics (Johari, 1985: 72).
However, normative theories rest on value preferences which cannot be tested or verified with factual experiments and this is an important difference from empirical/positivist theories. Moreover, they are not concerned with the proposition related to “what is” but “what ought to be, what should be” (Viotti and Kauppi, 1993:5;
Rosenau, 1993, 25; Frost, 1986: 15).
Empirical theories intensify on the real reasons of relations between statesmen and foreign policy. Diplomatic history introduces ample proofs for this perspective. From time to time, this contention is conducted in the axis of idealism-realism. However, the traces of the elements of value and norm would be seen in the studies carried out in the framework of realism as well. Therefore, this subjective factor could not be completely eliminated in empirical theories too. Empirical political scientists sometimes use the normative/philosophical concepts, even if they adopt empirical facts. In this context, coinciding theory and fact, inevitably, demonstrates the necessities that the empirical theories at the same time should utilize analytical approaches.

According to these information the correct answer is option E.