Choose the word or phrase among A, B, C or D that best fits the blank space in the following passage.

Email, and chat rooms let children communicate (6) ............. friends and family members. They can also allow children to connect with people that they have never (7) ............... in person. Knowing a little about each of these communication services can help parents (8) .................... children safer while online.

Through e-mail, (9) ............ can easily send and receive messages. These messages may also have text, audio, and  picture  files  attached.  Signing  up  for  an  email  account  is  simple (10) .............. most services offer them for free. Sometimes these messages contain viruses, or other inappropriate content, so  parents  should  warn  children  to  be  wary  of  email  from unknown people.

Chat rooms are online hang-out spots where anyone can talk about anything current events, books, and other common interests. Users often do not know each other in real life, so it is important that parents keep a close eye on the content of any conversations.

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

• A. 
  to
• B. 
  with
• C. 
  for
• D. 
  through