can you do me a favor ?

torn

I met a problem today, about english, i do not know the answer. so i am here to seek help.

the question is this:

" it ____ be great if you can give me a call."

A. would    B. can   C. should  D. could


I do not know which one is the best answer ?


Can you do me a favor ?   

please note why you choose one of them.

[s:5][s:5]