【正确答案】 C

【答案解析】[听力原文]
   When a sleepy driver has trouble in keeping his eyes on the road and gets too close to another car, an alarm sound will warn the driver. If nothing is done, the car will automatically come to a stop and in this way prevent an accident. This is a new device which will soon be tested in an experimental car in Japan. The computer warning system keeps track of a driver's condition by monitoring his heartbeat with signals transmitted from a band round his wrist. The wrist band records the driver's pulse which measures the heartbeat. Each pulse in the wrist sends a signal to the computer. By analyzing the pulse rate, the computer can determine whether a driver is drunk, sleeping or ill. Devices in other parts of the car can also tell the computer if the car is too close to another vehicle or is moving dangerously. The computer will sound the alarm when a problem arises, and will automatically stop the car if the driver ignores the warning.
   Why was a computer system installed in an experimental car?
通过录音第一句和第二句可知，研发此系统的目的是防止发生交通事故。