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Thadeus Inc. is a publicly traded chemical company with a bond rating of AA and a pre-tax cost of debt of 4.50% at its existing debt to capital ratio of 30% ($300 million debt & $ 700 million equity). The firm has operating income of $80 million and is considering borrowing $ 250 million and buying back stock. If it does so, what will the interest coverage ratio for the firm be, assuming that the firm's rating will drop to BBB and that the interest for BBB rated bonds is 6%? O a. 7.55 O b.3.28 O c. 2.42 O d. 5.64