A、Because these languages are used only in remote areas. B、Because the official language of a country rarely changes. C、Because

M: Sally, I heard from the radio that over half the world’s seven thousand languages are in danger of disappearing. Every two weeks one language disappears.
W: So fast?
M: Yes, so Mr. Harrison and Mr. Anderson are heading Living Tongues, an organization to study and protect endangered languages.
W: Why do these languages disappear?
M: Sometimes a language disappears immediately when the last person speaking it dies. Or, a local language might disappear more slowly. This happens when an official language is used more often and children stop learning the local language of their parents. This is not a new process. Official languages often represent a form of control over a group of people.
W: Can you explain it a bit further?
M: Throughout history, the language spoken by a powerful group spreads across a civilization. The more powerful culture rarely respects the language and culture of smaller ethnic groups. So, smaller cultures lose their local language as the language of the culture in power becomes the stronger influence.
W: I can see your point now.
M: The Internet could be thought of as a new method of language control. The United Nations cultural organization, UNESCO, says that ninety percent of the world’s languages are not represented on the Internet.
W: I guess we do need to protect these languages.
M: Experts say protecting languages is very important for many reasons. Languages contain the histories, ideas and knowledge of a culture. Languages also contain valuable information about local medicines, plants and animals. Bringing back threatened languages is not easy, but it is very important work.
W: No doubt. Questions 1 to 4 are based on the conversation you have just heard.
1. What is the organization Living Tongues aimed at?
2. Why do some cultures lose their local languages?
3. What is the Internet blamed for?
4. What does the speakers stress in the end?