A、  B、  C、  B题目为建议对付款条件进行讨论的建议疑问句。Why don’t we…是表示建议的表达。

Do you know why we installed the extra telephones?
(A)Yes, they just called.
(B)Our lines were always busy.
(C)About 14 cents per minute.

Why don’t we discuss the terms of payment?
(A)He has one term left.
(B)Sure, let’s take care of that.
(C)By credit card.