It costs Bluffton Company $18.20 of variable costs and $7.80 of fixed costs to produce its product that sells for $39. Cointreau Company, a foreign buyer, offers to purchase 3,000 units at $23.40 each. If the special offer is accepted and produced with unused capacity, net income will: increase $7,800. increase $11,700. increase $15,600. decrease $7,800.