I'm taking a test and have to guess the right answer to the question after the article. Article: One day a family visited the school where I taught deaf children. They said they would move here and planned to send their deaf daughter to my school as a first grader. They were upset that their child's kindergarten teacher told them not to have high hopes for her. Standing behind them was Katherine, a beautiful five-year-old with long hair and dark eyes. The whole time her parents were there, she didn't make a sound or use sign language, even when her parents asked her to do so. After a few weeks with Katherine, I discovered she was a very smart child. Although she joined in different learning activities, writing was always a problem . I tried all kinds of ways to get her interested in writing, but she always refused to write. One day Katherine got off the school bus and stood in front of the school crying. The teachers there did not know enough sign language to ask her what happened. Finally they led her into the office and gave her a pen and a piece of paper. Katherine wrote:"PACBAK". Then the teachers realized she had left her backpack on the bus. They called the bus driver back to school and soon Katherine got her backpack back. That day _ . From then on she fell in love with writing. She is a young woman now and has become an excellent writer, public speaker and student leader. Question: Why did Katherine cry in front of the school? Because . Options: A: she lost her pen. B: she left her backpack on the school bus. C: she fell off the school bus. D: she didn't know how to write" backpack"
B