Monterey Co. makes and sells a single product. The current selling price is $15 per unit. Variable expenses are $9 per unit, and fixed expenses total $27,000 per month. (Unless otherwise stated, consider each requirement separately.) b. Calculate the margin of safety and the margin of safety ratio. Assume current sales are $75,000. c. Calculate the monthly operating income (or loss) at a sales volume of 5,400 units per month.