value: 10.00 points Miller Metal Co. makes a single product that sells for $43 per unit. Variable costs are $28.6 per unit, and fixed costs total $65,340 per month. Required a. Calculate the number of units that must be sold each month for the firm to break-even. Do not round intermediate calculations.) Break-even volume 4,538 units b. Assume current sales are $406,000. Calculate the margin of safety and the margin of safety ratio. (Round intermediate calculations to the nearest whole number.) Margin of safety Margin of safety ratio c. Calculate operating income if 6,900 units are sold in a month. (Do not round intermediate calculations.)