It was not until the 18th century that man realized that the whole of the brain was involved in the working of the mind，　　　　？

A．was it

B．wasn’t it

C．did they

D．didn’t they

信用社的固定资产净值与在建工程之和占所有者权益（不含未分配利润）比例最高不得超过（）。

A.40%

B.50%

C.60%

D.70%