Figure 14-3 A graph of Total Cost versus Quantity of Output, which shows a curved line, increasing from left to right. It increases rapidly with quantity initially, reaches an inflection point, and then rises more slow as quantity increases, and finally begins to increase rapidly as quantity rises further. Refer to Figure 14-3. Why doesn't the total cost curve begin at the origin (the point 0,0)? a. Because the firm is producing at the efficient scale b. Because variable costs are positive when output is zero c. Because the firm is maximizing profits d. Because fixed costs are positive when output is zero