A graph of price, P, versus quantity, Q, is a demand curve consisting of a straight line descending from (0, P = A) to (Q = C, 0). Three points are shown on the curve. Point A is at (0, P = A), Point B is approximately at the midpoint of the line, and Point C is at (Q = C, 0). Refer to Figure 5-2. The section of the demand curve from A to B represents the elastic section of the demand curve. inelastic section of the demand curve. unit elastic section of the demand curve. perfectly elastic section of the demand curve