Annie Jump Cannon, ________ discovered so many stars that she was called "the census taker of the sky".

A．a leading astronomer,

B．who, as a leading astronomer,

C．was a leading astronomer,

D．a leading astronomer who

小企业金融服务专营机构，应建立独立的（）机制，对小企业金融服务的业绩考核要独立于其他银行业务，注重经营绩效和风险管理相结合。

A.风险定价

B.激励约束

C.成本利润核算

D.呆账核销