A firm has $100 in equity and $ 300 in debt. The firm recently issued bonds at the market required rate of 9 percent. The firm’s beta is 1.125, the risk-free rate is 6 percent, and the expected return in the market is 14 percent. Assume the firm is at their optimal capital structure and the firm’s tax rate is 40 percent. What is the firm’s weighted average cost of capital (WACC)（）

A. 7.8%.

B. 5.4%.

C. 8.6%.

正不敌邪或正气持续衰弱以致气不能内守，可导致的是（）

A.气陷

B.气脱

C.气郁

D.气结

E.气闭