The following is the production possibilities for a firm. At 0 labor units (strangely enough), there are 0 units produced. At 1 labor unit, there are 10,000 units produced, at 2 labor units, there are 25,000 units produced, at 3 there are 45,000, at 4 there are 60,000, at 5 there are 70,000, at 6 there are 75,000, at 7 there are 78,000, and at 8 there are 80,000. If the price of each unit produced is $ 3, and labor cost is 12,000 per unit, at what level should the firm produce?