产褥期持续的时间为（）

A.产后1月

B.产后6周左右

C.产后百天

D.产后10天

E.产后2周

The company has a target capital structure of 40 percent debt and 60 percent equity. Bonds pay 10 percent coupon (semi-annual payout ), mature in 20 years, and sell for $849.54. The company stock beta is 1.2. Risk-free rate is 10 percent, and market risk premium is 5 percent. The company is a constant growth firm that just paid a dividend of $2.00, sells for $27.00 per share, and has a growth rate of 8 percent. The company’s marginal tax rate is 40 percent. The after-tax cost of debt is:（）

A. 8.0%.

B. 9.1%.

C. 7.2%.