下列不属于房地产经纪业务中行政处罚风险的是（）。

A.不与交易当事人签订书面房地产经纪服务合同引起的风险

B.违规收取服务费引起的风险

C.未尽严格审查义务引起的风险

D.经纪服务合同未由房地产经纪人签字引起的风险

During the next ten years we both worked day and night to

_____ the money we had borrowed.

A．pay off

B．pay for

C．pay to

D．pay back