集存款、取款、贷款、消费、结算、查询为一体的信用工具是[ ]

A．支票　　

B．现金　

C．信用卡 　

D．电子货币

I just keep working hard as I have done, and ________ it will pay off. It has done so far and so I just have to do the same.

A．eagerly

B．hopefully

C．immediately

D．gradually