影响桩冠固位力的因素包括（）。

A.冠桩的长度

B.冠桩的直径

C.冠桩的材料

D.冠桩的形态

E.根管治疗完的时间

An analyst does research about interest rate policy tools. In implementing monetary policy, which of the statements is NOT used as an interest rate policy by the U. S. Federal Reserve（）

A. Bank reserve requirements.

B. The prime rate.

C. Verbal persuasion to influence how banks supply credit to businesses and consumers.