2. Callan Corporation manufactures and sells a special kind of ball bearing. Its cost structure depends on the number of bearings it produces. Its fixed costs and variable manufacturing cost per unit for different ranges of production are described in the following table: Callan's sales director believes the company can sell 2,400 units at a selling price of $400; or 3,400 units at a price of $250; or 6,900 units at a price of $200. If it chose to sell 6,900 units, however, it would incur additional advertising costs of $60,000 and variable selling costs of $11 per unit. Should Callan Corporation plan to produce and sell (a) 2,400 units (b) 3,400 units or (c) 6,900 units