.I remember putting the tape recorder in the corner, but what _______ it?

1. A.
   has happened on
2. B.
   has become of
3. C.
   has happened
4. D.
   has taken

.

I remember putting the tape recorder in the corner, but what _______ it?

   A. has happened on  B. has become of    C .has happened   D. has taken

.
I remember putting the tape recorder in the corner, but what _______ it?