This passage is mainly about ______.

A．The borderline between the common good and personal privacy is no longer elusive.
B．With the development of information technology even highly skilled and professional functions may become obsolete.
C．People can never catch up with the rate of obsolescence of knowledge.
D．People who are given access to information are literate.

A．the use of video conferencing is still a mystery for the general public
B．video conferencing may be as simple as telephones for communication
C．face to face relationship is important for customers and suppliers
D．video conferencing is especially popular with information technology firms