Music lessons are interesting for some people. Mozart was such a boy. He couldn’t wait to start. When he was three years old, he had music lessons with his elder sister. And when he was five, he was making up his own music. But some people thought the little boy couldn’t write such beautiful music. They thought his father had written it. They asked Mozart to stay in a room all by himself for a week. Someone watched the room all the time. No one could talk to him. At the end of the week, he had written a new piece of music. Mozart died when he was young. But in his short life he wrote more than 560 pieces of music. Some people asked Mozart to stay in a room by himself because they wanted to know whether ______
A. his father was a good music teacher. B. his father often helped him with music. C. he really could write music by himself.