Gundy Company manufactures a product with the following costs per unit at the expected production of 30,000 units: Direct materials $4 Direct labor 12 Variable overhead 6 Fixed overhead 8 The company has the capacity to produce 30,000 units. The product regularly sells for $40. A wholesaler has offered to pay $32 per unit for 2,000 units. If the firm chooses to accept the special order and reject some regular sales, the effect on operating income would be a. $-0-. b. a $20,000 increase. c. a $16,000 decrease. d. a $4,000 increase