The Internet is not perfect. There are many problems with it. The Internet is not organized. There is no one in charge of the Internet. It is sometimes difficult to find what you are looking for. It is also easy to get the wrong information on the "Net". Some businessmen cheat people on the Internet. Internet thieves can steal credit card numbers. Some advertisers send spam to e-mail boxes. E-mail boxes are often filled with these unwanted advertisements. Illegal businesses can operate on the Internet. These businesses sell X-rated materials, cigarettes and alcohol to teenagers. The Internet has websites with information about making bombs, breaking the law and terrorism. Criminals can fool people, especially children, in chat rooms. They can spread poisonous information and attack new members. The Internet is the greatest advance in communication since human emerged. But it can also like a dark alley in a dangerous part of town. Parents need to set parental controls on their children when they use the Internet. This will keep some of the bad material away from their children. The Internet can be dangerous to computers, too. Some people who have evil intentions enjoy causing problems for other people they don't even know. They create computer viruses. A computer can get virus by downloading a program that has a virus in it. Some virus come by e-mail. A virus can destroy the data a person has saved in computer files. A virus can cause a computer to crash. A virus can also reproduce itself! It can send copies of itself to everyone on a person's e-mail address list. Then these people's will have the same problems and can't work normally! We can infer from the passage that the key to solving the problems with the Internet is  _
to improve the computers to find a medicine to kill computer viruses to order people not to use the Internet to improve people's moral level .
Question: The Internet is not perfect. There are many problems with it. The Internet is not organized. There is no one in charge of the Internet. It is sometimes difficult to find what you are looking for. It is also easy to get the wrong information on the "Net". Some businessmen cheat people on the Internet. Internet thieves can steal credit card numbers. Some advertisers send spam to e-mail boxes. E-mail boxes are often filled with these unwanted advertisements. Illegal businesses can operate on the Internet. These businesses sell X-rated materials, cigarettes and alcohol to teenagers. The Internet has websites with information about making bombs, breaking the law and terrorism. Criminals can fool people, especially children, in chat rooms. They can spread poisonous information and attack new members. The Internet is the greatest advance in communication since human emerged. But it can also like a dark alley in a dangerous part of town. Parents need to set parental controls on their children when they use the Internet. This will keep some of the bad material away from their children. The Internet can be dangerous to computers, too. Some people who have evil intentions enjoy causing problems for other people they don't even know. They create computer viruses. A computer can get virus by downloading a program that has a virus in it. Some virus come by e-mail. A virus can destroy the data a person has saved in computer files. A virus can cause a computer to crash. A virus can also reproduce itself! It can send copies of itself to everyone on a person's e-mail address list. Then these people's will have the same problems and can't work normally! We can infer from the passage that the key to solving the problems with the Internet is  _
A. to improve the computers
B. to find a medicine to kill computer viruses
C. to order people not to use the Internet
D. to improve people's moral level .
Answer: