Figure 15-1 Suppose that a firm in a competitive market has the following cost curves: A graph of Price, P, versus Quantity, Q, which shows a curved, upward-sloping line, M C, rising from about (1.3, 4.7) to (3.3, 20), and two curved lines, A V C and A T C, both decreasing at a decreasing rate, reaching a minimum, and then from that point increasing at an increasing rate. A T C lies above A V C at all quantities. Line M C intersects both curved lines at the minimum points. A horizontal drop line extends from P = 6, ending at the intersection of MC and A V C at Q = 2. A horizontal drop line extends from P = 13, ending at the intersection of M C and A T C at Q = 3. Refer to Figure 15-1. The firm should shut down if the market price is a. above $6 but less than $13. b. above $13. c. less than $6. d. above $6 but less than $18