Which of the following statements about capital is incorrect?

A) a company's target capital structure affects its weighted average cost of capital

B) Weighted average cost of capital calculations should be based on the after-tax-costs of all the individual capital components

C) if a company's tax rate increases, then, all else equal,its weighted average cost of capital will increase

D) the cost retained earnings is equal to the return stockholders could earn on alternative investments of equal risks

E) flotation costs can increase the cost of preferred stock