题目4单选题
Basically , how does a rack-and-pinion system workA. A rack-and-pinion gesr set is enclosed in a tube that turns a tire rack. The tire rack turns the car's wheelsB. A rack is connected to the steering wheel , which turns the pinion that turns the car's wheelsC. A spindle moves the pinion , which sits on a rackD. The sleering ann moves the pinion , which powers the rack to turn the wheels