Which of the Following Statements Best Describes WACC

Which of the following statements best describes WACC?

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 the 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.