The graph shows a point of equilibrium.

A graph has Quantity supplied on the x-axis and price in dollars on the y-axis. A line that represents supply has a positive slope and a line that represents demand has a negative slope. The lines intersect at point (30, 9). Line P is drawn from the point of equilibrium to the y-axis, and line Q is drawn from the point of equilibrium to the x-axis. What does "Q” represent on the graph?

the point where equilibrium is achieved
the quantity at the equilibrium point
the average cost of goods sold
the point where supply and demand drop