单选题 Mozart began to study music ______ [A] when he was a little boy. [B] when he was five years old. [C] when his father wrote some pieces of music.

【正确答案】 A

【答案解析】[解析] 原文的第一段中的第二行和第三行明显表示出：“When he was three years old，he had music lessons with his elder sister”。