Which of the following statements is true for a company with a positive gross margin?

A. A 10% increase in sales has the same impact on free cash flow as a 10% reduction in cost of sales

b. A 15% increase in sales has a smaller impact on free cash flow than a 15% reduction in cost of sales c. A 20% increase in sales has a larger impact on free cash flow than a 20% reduction in cost of sales

d. None of the above