[单项选择]

[听力原文]
The colorful Internet draws us to computers and brings us joy and wealth. However, it is also affecting our health, because of increased computer use. Some people humorously call these negative effects the "six destructive fists of the Internet".
First, it damages the eyes. However good your monitor is, whether it is low-radiant or LCD, you will definitely feel light-headed after a day of web-surfing.
Secondly, it damages the hands. The constant repetitious movements will make your fingers and wrists sore and aching.
Thirdly, it damages the mouth. When people are roaming in the sea of the Internet and chatting with the keyboard, the mouth is the most unused organ.
Fourthly, it hurts the back. People will sit motionless in front of computers for several hours. Their midsections and skeletal systems suffer the most.
Fifthly, it damages the stomach. It is almost impossible for web-surfers to have healthy stomachs. They
A. The high speed and efficiency of the Internet.
B. The health problems due to addiction to the Internet.
C. The joy and comfort provided by the Internet.
D. The irresistible attraction of the Internet.