Which of the following statements regarding the weighted average cost of capital (WACC) is correct?

a A change in a company's target capital structure cannot affect its WACC.

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

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

d If a company's tax rate increases, then all else equal, its WACC will decline.