4. Suppose a new company decides to raise a total of $200 million, with $100 million as common equity and $100 million as long-term debt. The debt can be mortgage bonds or debentures, but by an iron-clad provision in its charter, the company can never raise any additional debt beyond the original $100 million. Given these conditions, which of the following statements is CORRECT?

a. The higher the percentage of debt represented by mortgage bonds, the riskier both types of bonds will be and, consequently, the higher the firms total dollar interest charges will be.

b. If the debt were raised by issuing $50 million of debentures and $50 million of first mortgage bonds, we could be certain that the firms total interest expense would be lower than if the debt were raised by issuing $100 million of debentures.

c. In this situation, we cannot tell for sure how, or whether, the firms total interest expense on the $100 million of debt would be affected by the mix of debentures versus first mortgage bonds. The interest rate on each of the two types of bonds would increase as the percentage of mortgage bonds used was increased, but the result might well be such that the firms total interest charges would not be affected materially by the mix between the two.

d. The higher the percentage of debentures, the greater the risk borne by each debenture, and thus the higher the required rate of return on the debentures.

e. If the debt were raised by issuing $50 million of debentures and $50 million of first mortgage bonds, we could be certain that the firms total interest expense would be lower than if the debt were raised by issuing $100 million of first mortgage bonds.