Wisconsin Company has a current production capacity level of 200,000 units per month. At this level of production, variable costs are $1.00 per unit and fixed costs are $0.50 per unit. Current monthly sales are 164,500 units. Gates Company has contacted Wisconsin Company about purchasing 20,000 units at $2.00 each. Current sales would not be affected by the special order and no additional fixed costs would be incurred on the special order. Variable costs would increase $0.10 per unit with the special order. If the order is accepted, what is Wisconsin Company's increase in operating income? A) $8,000 B) $18,000 C) $20,000 D) $24,000