Choose the sentence that is closest in meaning to each of the following questions.Câu hỏi He gains impressive achievements at the age of 20. A. It is at the age of 20 that he gains impressive achievements. B. It was at the age of 20 that he gains impressive achievements. C. It is at the age of 20 who he gained impressive achievements. D. It was at the age of 20 that he gained impressive achievements.