The following is Billy Corporation's contribution format income statement for last month: Sales $1000,000 Variable expenses 600,000 Contribution margin 400,000 Fixed expense 250,000 Net operating income 150,000 The Company has 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. How many units would the company have to sell to attain a target profit of $125,000? d. What is the company's margin of safety in dollars