Which of the following is the correct interpretation of a degree of operating leverage of 5? a. Operating leverage of 5 measures the degree of debt employed by the firm's debt structure b. Operating leverage of 5 means that if sales increase by 5%, there will be a 25% increase in the firm's profit c. Operating leverage of 5 means that the company would need to increase sales by 5 times in order to hit its break-even point d. Operating leverage of 5 means that sales can decrease by 5% before the firm's current level of sales will hit the break-even point