Figure 311 Alt Text for Figure 3

Figure 3.11 Alt text for Figure 3.11: In figure 3.11, a graph plotting intersecting supply and demand curves illustrates how supply and demand function in competitive markets.
Long description for Figure 3.11: The x-axis is labelled, Quantity, and is marked from 0 to 8 in increments of 2.The y-axis is labelled, Price, and is marked from 0 to 20 dollars in increments of 5.Curve D is a straight line which slopes down from the top left corner to the bottom right corner.Curve S is a straight line which begins in the bottom left corner and slopes up to the top right corner.The equilibrium of the 2 curves is marked at (4,10) .2 points plotted on the demand curve to the left of the equilibrium are (0,20) and (2,15) .2 points plotted on the demand curve to the right of the equilibrium are (6,5) and (8,0) .2 points plotted on the supply curve to the right of the equilibrium are (6,15) and (8,20) .2 points plotted on the supply curve to the left of the equilibrium are (2,5) and (0,0) .
-Refer to Figure 3.11.At a price of $15, the quantity sold

A) is 2 units.
B) is 4 units.
C) is 6 units.
D) cannot be determined.