The following is Knox Corporation's contribution format income statement for last month: Sales $900,000 Less: variable expenses 300,000 Contribution margin 600,000 Less: fixed expenses 400,000 Operating income $200,000 The company has no beginning or ending inventories. The company produced and sold 10,000 units last month. What is the company's contribution margin ratio? 62.5%. 160%. 500%. 66.7%.