Which of the following statements is most accurate regarding a firm’s cost of preferred shares A firm’s cost of preferred stock is:（）

A. the market price of the preferred shares as a percentage of its issuance price.

B. the dividend yield on the firm’s newly-issued preferred stock.

C. approximately equal to the market price of the firm’s debt as a percentage of the market price of its common shares.

患者．女，31岁。3年来怀孕3次，均不足3个月而流产，听力减退，带下清稀，腰部酸痛，舌淡苔白，脉弱。其证候是

A．肾气不固
B．肾精不足
C．肾阳虚
D．中气下陷
E．脾肾阳虚