The following are ABC Company's unit costs of making and selling an item at a volume of 8,000 units per month (which represents the company's capacity); Manufacturing: Direct materials $4 Direct labor $3 Variable overhead $2 2 Fixed overhead $3 Selling and administrative: Variable $1 Fixed $6 Present sales amount to 7.000 units per month. A special order has been received from a customer in a foreign market for 1,000 units for $20 per unit. The order would not affect regular sales. Total fixed costs, both manufacturing and selling and administrative, would not be affected by this order. The variable selling and administrative costs would have to be incurred for this special order as well as all other sales. ABC Company usually sells the units for $25 per unit. What is the impact on operating income if ABC Company accepts the special order? $8,000 decrease O $8,000 increase O $5,000 decrease O $10,000 decrease O $10,000 increase