Scientists generally agree that Earth's climate will warm up over the next 50 to 100 years ________ it has warmed in the 20,000 years since Ice Age.

A．so long as

B．as much as

C．as long as

D．as well as

某钢铁公司与机械进出口公司签订购买价值2000万元设备合同，为购买此设备向商业银行签订借款2000万元的借款合同。后因故购销合同作废，改签融资租赁合同，租赁费1000万元。根据上述情况，该厂一共应缴纳印花税为（）。

A．1500元

B．6500元

C．7000元

D．7500元