听力原文： City traffic is a great problem. More cars are produced every year and the stree

ts are getting more and more crowded. So during" rush hours", when people are going to or from their work, traffic is brought to a standstill. It has been suggested that commuters should share their cars and give each other lifts. It is an excellent idea, however, so far nobody has been able to think of a way to compel people to do so.

To discourage motorists from leaving their cars in the streets all day, parking meters are used. When you park at a meter, you will pay a coin. This pays for a certain amount of time. The meter re cords this and it shows when the time that you have paid for is finished. If the car is still there then, you have to pay a fine.

Traffic wardens look after the meters. They walk around the streets and check that every meter shows that money has been paid for the car parked there. If a meter registers" time expired", the motorist who has left his car there is fined. Of course, the traffic :warden cannot wait for the owner of car to return. He carries a block of printed forms, and on one of these he writes down all the details, such as the registration number of the car, where it is parked, how much the driver must pay and where he must send the money. He leaves this form. on the car where the driver will be able to see it easily; he usually pushes it under one of the windscreen wipers so that it will not blow away. And in case it rains before the motorist returns, the form. is put in a little plastic envelope to protect it. When the driver comes back, he gets an unpleasant surprise, but it is his own fault for leaving his car too long at a parking meter.

What is "rush hours"？

A．A period when cars are rushing on the roads.

B．A period when people are going to or from their work.

C．A period when cars are crowed on the roads.

D．A period when people are crowed in the buses.