Commercial banks usually quote four prices when they buy or sell foreign exchange: the central parity rate, the spot purchase rate, the cash purchase rate and the selling rate. Under the direct quotation, the highest and lowest prices are usually（）

A.selling rate and the cash purchase rate

B.central parity and spot purchase rate

C.spot purchase rate and cash purchase rate

D.spot purchase rate and selling rates

正确答案：selling rate and the cash purchase rate