One day in 1965, when I was a library worker at school, a teacher came to me. She had a student who finished his work before all the others and needed something more difficult for him to do. "Could you help me in the library?" she asked. I said, "Send him along." Soon, a golden-haired boy appeared. "Do you have a job for me?" he asked. I told him about a system for sorting books. He picked up the idea immediately. Then I showed him some cards for some unreturned books that I thought had been returned but not recorded. Maybe some books were put on wrong places. He said, "Is it a kind of a detective (侦探) job?" I answered yes, and then began his work. He had found three books with wrong cards by the time his teacher opened the door and said, "Time for rest!" he argued for finishing the finding job, but the teacher won. The next morning, he arrived early, "I want to finish these books," he said. At the end of the day, when he asked to work with me more often, it was easy for me to say yes. After a few weeks I found a note on my desk, inviting me to dinner at the boy's home. At the end of a pleasant evening, his mother declared that the family would be moving to another school. Her son's first concern, she said, was leaving the library. "Who will find the lost books?" he asked. When the time came, it was hard to say goodbye. Though at the beginning he had seemed an ordinary boy, his strong feeling of interest had made him different. Do you know who he is? This boy became a great man of the Information Age: Bill Gates.91)Why did the teacher go to the library to find a job for Bill Gates?
选项：

A: Because the teacher found the librarian quite busy.
B: Because Bill Gates wanted to find a job.
C: Because Bill Gates finished his study quickly and had more free time than the others.
D: Because the library needed a new worker.