One of the oldest and most widely accepted political theories is realism. There are several theorists and their works that are regarded as classics of realism. Many date realism’s initial formulation back to the writer Thucydides in his History of the Peloponnesian Wars (341-301 BCE).Thucydides wrote his  masterwork as a disgraced general, sometimes from second-hand sources, of the events of the Peloponnesian  War.   Hobbes are considered by some    experts to be the forefathers of today’s realist approaches to IR. As also understood from the information given, the correct answer is B. John Locke and Adam Smith were two who had significant influence on the assumptions of idealism, the foundation of classical liberalism.