Internet users posted photos showing a huge crack on the roof of a factory in Shanghai and said what looked like part of a plane had fallen through its roof. The triangular component with a length of less than one meter fell into the factory but luckily no one was injured. According to the aviation authority, the part has been confirmed as a component from a Boeing 777, which closes up the undercarriage to seal the space. Its absence doesn't affect the plane's flight itself but is clearly a potential hazard to people on the ground.

How many people were injured after a huge crack on the roof of the factory?

A. None

B. 7 people

C. 777 people

（中國日報網(wǎng)英語點津 Helen 編輯）