It is still unclear ______ the little boy got the CD player to work．

1. A.
   where
2. B.
   what
3. C.
   that
4. D.
   how

It is still unclear ______ the little boy got the CD player to work．

       A．where      B．what      C．that D．how

It is still unclear ______ the little boy got the CD player to work．