The following diagram shows the market demand for steel. Use the orange points (square symbol) to plot the initial short-run industry supply curve when there are 20 firms in the market. (Hint: You can disregard the portion of the supply curve that corresponds to prices where there is no output since this is the industry supply curve.) Next, use the purple points (diamond symbol) to plot the short-run industry supply curve when there are 40 firms. Finally, use the green points (triangle symbol) to plot the short-run industry supply curve when there are 60 firms