Where's the marginal revenue, what's the marginal revenue look like in this picture on the left?

边际收益是什么样子的,左图中的边际收益图像是什么样的

耶鲁公开课 - 博弈论课程节选

What does the marginal revenue look like in this picture?

这个图像中的边际收入是什么呢

耶鲁公开课 - 博弈论课程节选