Wall mart Manufacturing produces a product that sells for $75. Fixed costs are $350,000 and variable costs are $28 per unit. Winthrop can buy a new production machine that will increase fixed costs by $13,200 per year, but will decrease variable costs by $2 per unit. Compute the contribution margin per unit if the machine is purchased. O a. $45.00. O b. $40.00. O c. $52.00. O d. $51.00. O e. $49.00