下列哪种是性病传播最危险的行为

A．一名男性与暗娼有不用避孕套的 * * 性交

B．与一名暗娼行手淫服务

C．两名男性间有无保护的口交行为

D．与一名偶遇的外国人发生的性行为

E．一名男性与暗娼有非插入的性交

Which of the following choices best describes the role of taxes on the after-tax cost of capital in the U. S. from the different capital sourcesCommon equity Preferred equity Debt（）①A. No effectDecrease Decrease ②B. DecreaseDecrease No effect ③C. No effectNo effect Decrease

A. ①

B. ②

C. ③