nowadays paying _______ credit card is easier and safer than carrying a lot of "real" money.

问题描述:

nowadays paying _______ credit card is easier and safer than carrying a lot of "real" money.
A.for B.by C.with D.on
请说明理由.

选B by表示方式,是固定搭配,用什么什么付钱的意思,这句话的意思是说:现如今,用信用卡付钱比带着很多现金要简单方便的多