–I think it’s going to be a big problem.

--Yes, it could be.

--I wonder ________ we can do about it.

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

---I think it’s going to be a big problem.
---Yes, it could be.
---I wonder ______ we can do about it.

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

--- I think it's going to be a big problem.

--- Yes, it could be.

--- I wonder          we can do about it.

A. if                        B. how

C. what                     D. that