Consider the following cost function: = 144 + 3 + 2 (a) What are the formulas for the fixed cost, variable cost, average (total) cost, average variable cost, and marginal cost? (b) At what level 1is average cost lowest? What is the lowest average cost? (c) At what level 2 is average variable cost lowest? What is the lowest average variable cost? (d) Discuss at which output levels, this firm has economies of scale or diseconomies of scale?