听力原文： In 1985 a French television company sent its reporters to the Paris Metro. They

took cam- eras to see what passengers would do when they saw someone attacked on the platform. or trains. The incidents looked real but they were all done with the help of actors. However, very few people tried to help, and most passengers pretended not to notice. In one incident, a foreigner was attacked by three men. The attack was on a train which was quite full, and although one man tried to get the other passengers to help, they all refused. It seems that such behaviour is not unusual, but the question is why？ Is it a problem of big cities, or would the same thing happen anywhere？ You're welcome to discuss these questions with Professor Wilson who is an expert in the subject. . .

Who did the experiment？

A．A French television company.

B．The Paris Metro.

C．The City Government of Pairs.

D．Professor Wilson.