Concept:Emphatic stress is used to correct a wrong idea in a question by emphasising the exact word that is challenged.Explanation:The emphasised word is WON.So the reply corrects an action of losing, not winning.The suitable question is: “Did Omo's brother lose a radio?”The reply becomes: “No, Omo's brother WON a radio.”All other options change the wrong element, such as the person or the object.Answer:A. Did Omo's brother lose a radio?