_____quite common for people to believe that more and more teenagers have become addicted to on line games.

1. A.
   As is
2. B.
   That is
3. C.
   It is
4. D.
   What is

_____quite common for people to believe that more and more teenagers have become addicted to on line games.?

A.As is                            B.That is     C.It is                            D.What is ?