4. Last year, Adelajdia Ago Co. reported $1,440,000 in sales (36,000 units) and an operating income of $508,200. At the break-even point, the company's total contribution margin equals $499,800. Based on this information, which of the following statements is true? a) The company's contribution margin ratio is 60%. b) The company's break-even point is 20,000 units. 0) The company's variable expense per unit is $12. d) The company's variable expenses are 40% of sales