Which of the following statements is CORRECT? a. Firms with more liquid assets, which tend to have lower bankruptcy costs, tend to use less debt. b. If changes in the bankruptcy code make bankruptcy less costly to corporations, then this would likely reduce the debt ratio of the average corporation. c. An increase in the corporate tax rate is likely to encourage a company to use more debt in its capital structure. d. An increase in the company's degree of operating leverage is likely to encourage a company to use more debt in its capital structure.