Concept:Nahum's message is an oracle of judgment against a single powerful city.Explanation:The Book of Nahum is entirely devoted to declaring the downfall of Nineveh.Nineveh was the capital of the Assyrian Empire, Israel's cruel enemy.Nahum announced that Nineveh's wickedness and oppression would lead to its complete destruction.Thus, his prophecy directly concerns the impending doom of that city.Answer:C. Nineveh