Which of the following actions would reduce a company's Weighted Average Cost of

a$.$ The company uses the dividend model to calculate the cost of internal equity, a

b$.$ The company's corporate tax rate decreases

c$.$ The company uses the CAPM to calculate the cost of internal equity, and the

d$.$ The company's debt is rated as less risky, and the yield to maturity on newly

e$.$ An increase in the flotation costs associated with issuing new common stock