Concept:A one-word substitute names a person by a key quality or attitude.Explanation:The phrase describes a person who treats the whole world as his own country.Such a person is not confined to one nation and feels at home everywhere.The word "Cosmopolitan" means a citizen of the world.Other options do not fit:"Cynosure" means centre of attraction."Contemporary" means belonging to the same time."Coquette" means a flirtatious woman.Answer:Option B: Cosmopolitan.