Michel is a young girl who works for the police as a handwriting expert ( 专 家 ). She has helped catch many criminals (罪犯) by using her special talents (天才).
When she was fourteen, Michel was already ___1___ interested in the differences in her friends’ handwriting that she would spend hours studying them. After finishing college she went to France for a special two-year class___2___handwriting at the School of Police Science.
Michel says that it is ___3___ for people to hide their handwriting. She can discover most of what she needs to know simply by looking at the writing with her own eyes, but she also has machines that help her make out different kinds of paper and ink. This knowledge is often of great help to the police.
Michel believes that handwriting is a good___4___of what kind of person the writer is. "I wouldn’t go out with a fellow if I didn’t like his handwriting.” She says. But she adds she fell in love with her future husband, a young policeman, ___5___she studied his handwriting. It is later proved to be all right, however.
根据短文内容，在A、B、C、D、E五个选项中，选出最佳答案填入文中(4)处。

A.in

B.so

C.impossible

D.sign

E.before