Compute the present value of interest tax shields generated by these three debt issues. Consider corporate taxes only. Assume that the marginal tax rate is Tc = 0.40. a. A $2,800, one-year loan at 10%. (Do not round intermediate calculations. Round your answer to 2 decimal places.) Present value b. A four-year loan of $2,800 at 10%. Assume no principal is repaid until maturity. (Do not round intermediate calculations. Round your answer to 2 decimal places.) Present value c. A $2,800 perpetuity at 9%. Present value