Financial Leverage Refers to Which of the Following

Financial leverage refers to which of the following?

A) The difference between the rate of return earned on assets (ROI) and the rate of return earned on stockholders' equity (ROE) .
B) The difference between the rate of return earned on current assets and the rate of return earned on retained earnings.
C) The leverage a firm obtains from increasing production.
D) Decreasing fixed costs per unit by increasing production.