Along with the letter was his promise ________ he would pay me a visit next month．

1. A.
   that
2. B.
   which
3. C.
   whether
4. D.
   what

Along with the letter  was his promise ______ he would pay me a visit next month.

A．that            B．which         C．whether         D．what

 Along with the letter  was his promise ______ he would pay me a visit next month.

A. that               B. which              C. whether           D. what