The following is Arkadia Corporation's contribution format income statement for last month: Sales........ $1,200,000 Variable expenses...... 800,000 Contribution margin.. 400,000 Fixed expenses....... 300,000 Net operating income............. $ 100,000 The company has no beginning or ending inventories and produced and sold 20,000 units during the month. Required: a. What is the company's contribution margin ratio? b. What is the company's break-even in units? c. If sales increase by 100 units, by how much should net operating income increase? d. How many units would the company have to sell to attain target profits of $125,000? e. What is the company's margin of safety in dollars