A diner has no competition when it comes to its famous Reuben sandwich combo plate, for which the graph shows the diner's demand (D), marginal cost...

A diner has no competition when it comes to its famous Reuben sandwich combo plate, for which the graph shows the diner's demand (D), marginal cost (MC), and marginal revenue (MR) curves. The price of $20 is based on the MR = MC rule for profit maximization. The rectangular region shown represents the