We are disappointed to note that so far we have not received you

We are disappointed to note that so far we have not received your L/C which ______ us before April 1st.
A、shall reach
B、must have reached
C、should have reached
D、is reaching
【正确答案】：C
【题目解析】：should have done本应该干某事句意：我们很遗憾地注意到，到目前为止我们还没有收到你方信用证，该信用证应在4月1日前到达我方。