Mark the letter A, B, C or D to indicate the sentence that best combines the following pairs of sentences.Câu hỏi "The boy is my cousin. He won the first prize in the competition." A. The boy is my cousin whose won the first prize in the competition. B. The boy who won the first prize in the competition is my cousin. C. The boy whom won the first prize in the competition is my cousin. D. The boy, which won the first prize in the competition, is my cousin.