C
It was Sally's first time alone on a bus to school. She was excited and a bit nervous. The bus stop was near her house, but today, it seemed to be miles away. Sally finally got on the bus and took a seat by a window in the back row.
The bus started at a normal speed. But Sally felt that something seemed to be wrong because there was a terrible smell coming out of the back of the bus. She saw some people next to her looked as if they were getting sick. Suddenly, she realized that it probably was a gas leak (泄漏). She had to do something. She shouted to the bus driver, but he didn't hear her. Then she tried to open the windows, but they were locked due to the air-conditioning (空调).
Just then, she looked down, and saw her rock-hard shoes. She immediately took off one of them and,with much strength, broke open the window nearest to her, letting out the gas, and bringing the attention of the driver to the trouble.
She was afraid that the driver would have her arrested (逮捕) for breaking the window when a policeman came. But to her surprise and delight, the policeman expressed his thanks for her help.
When she arrived at the school, she told the story to her teacher and classmates. They were very proud of her.

How did Sally feel before she got on the bus to school alone?