Which of the following statements is CORRECT?

a. A change in a companys target capital structure cannot affect its WACC.

b. WACC calculations should be based on the before-tax costs of all the individual capital components.

c. Flotation costs associated with issuing new common stock normally reduce the WACC.

d. If a companys tax rate increases, then, all else equal, its weighted average cost of capital will decline.

e. An increase in the risk-free rate will normally lower the marginal costs of both debt and equity financing.