Write a multi-choice question for the following article, with the given choices and answer: Article: Ole Bull was a very famous violinist from Norway. He really liked to play the violin. But his father thought that playing the violin was not useful. So his father sent him to university to study. However, playing the violin was his dream. He didn't want to give up his dream. So he left university before he finished his studies and spent all his time and energy practicing the violin. Unfortunately, his violin teacher was not very good. So when it was time for him to start his concert tour, he still couldn't play the violin very well. Therefore, a Milan newspaper critic1criticized him and said that he was an untrained violinist. The critic said, " _ 2yet." When facing this kind of problem, some people may become very angry and some people try to learn from it. Fortunately, Ole Bull belonged to the second group. He went to the newspaper office and found the critic. Instead of being angry, he talked about his mistakes with the man and listened to the man's advice. After he met the critic, he gave up the rest of his concerts. Then he went back to practice the violin with the help of good teachers. In the end, he got great success when he was only 26. He also became one of the most famous violinists in the world. Options: A Because he thought playing the violin was useless. B Because his father thought playing the violin would cost lots of money. C Because his father thought he couldn't play the violin well. D Because his father thought he couldn't make his dream come true. Answer: A Because he thought playing the violin was useless. Question:
Why didn't Ole Bull's father like him to play the piano?