Concept:The underlined word is “famous”, meaning known by many people.Explanation:We need the word that is most nearly opposite in meaning to “famous”.“Infamous” means well-known for a bad reason, so it is not the opposite.“Unknown” means not known by people, which is the true opposite of “famous”.“Humble” and “unpopular” do not directly oppose “famous”.Thus, the correct word to fill the gap is “unknown”.Answer:C. unknown