Which of the following statements is CORRECT? a. Other things held constant, the more debt a firm uses, the higher its operating margin will be. b. Debt management ratios show the extent to which a firm's managers are attempting to magnify returns on owners' capital through the use of financial leverage. c. Other things held constant, the more debt a firm uses, the higher its profit margin will be. d. Other things held constant, the higher a firm's debt ratio, the higher its TIE ratio will be. e. Debt management ratios show the extent to which a firm's managers are attempting to reduce risk through the use of financial leverage. f. The higher the debt ratio, the lower the risk.