I ______ to know about this.

A．more and more people have lost interest in spending money
B．more and more people are going to ask for Credit cards
C．credit cards are taking the place of cash
D．credit cards are worth more than cash

A．you must pay for what you have bought immediately
B．you don't have to pay for what you have bought
C．you must pay for what you have bought once in a while
D．you can pay for what you have bought either at one time or at several times