How were great musicians different from ordinary musicians in their development

* Hướng dẫn giải

Đáp án là D. Dựa vào ý trong đoạn 6: One professor of music said that outstanding musicians usually started two or three years earlier than ordinary performers, often because their parents had recognized their ability. These musicians then needed at least ten years’ hard work and training in order to reach the level they were capable of attaining.