28. Simon Software Co. is trying to estimate its optimal capital structure. Right now, Simon has a capital structure that consists of 20% debt and 80% equity. (Its D/E ratio is 0.25). The risk-free rate is 6% and the market risk premium, km KRF, is 5%. Currently the company's cost of equity, which is based on the CAPM, is 12% and its tax rate is 40%. What would be Simon's estimated cost of equity if it were to change its capital structure to 50% debt and 50% equity? a. 14.35% b. 30.00% c. 14.72% d. 15.60% e. None of the Above