I will appreciate it very much ________ you could change your plan a little bit to make it more workable．

1. A.
   if
2. B.
   that
3. C.
   whether
4. D.
   unless

I will appreciate it very much ________ you could change your plan a little bit to make it more workable．

A．if                           B．that                        C．whether                  D．unless