the answer is neither a or b. please help ;)

hich of the following statements about the cost of capital is CORRECT? a. The WACC of a firm will decrease when investors become more risk averse. b. Both the cost of debt and equity financing will decrease when a nuclear plant company encounters a ban on nuclear power generation in certain states. c. Both the cost of debt and equity financing will decrease when a firm increases its debt/asset ratio. d. If a company's tax rate increases, then, all else equal, its weighted average cost of capital will decrease. e. Both the cost of debt and equity financing will decrease when a firm expands into a risky new area