Keys Printing plans to issue a $1,000 par value, 20-year noncallable bond with a 9.60% annual coupon, paid semiannually. The company's marginal tax rate is 40.00%, but Congress is considering a change in the corporate tax rate to 25.00%. By how much would the component cost of debt used to calculate the WACC change if the new tax rate was adopted? Do not round your intermediate calculations.

a. 1.44%

b. 0.36%

c. 2.88%

d. 0.72%

e. 0.24%