Choose the letter A, B, C or D to complete the passage below

The Internet was born (6) _________scientists attempted to connect the American Defence Network to other satellite networks in (7) _________to exchange information. Soon, scientific and educational institutions as well as research departments became interested (8) _________ linking up, and, before long, the Internet had expanded into an international information and communication network.

The Internet now (9) _________ all the countries in the world. You can be connected to the Internet directly through your own computer or you can hook up to (10) _________ access system which allows you to use some of the Internet’s services.

(6) ...................

• A. 
  what
• B. 
  where
• C. 
  when
• D. 
  who