Issues in Economics Today 7th Edition by Robert Guell

Exercise 1

In a diagram of perfect competition, the marginal revenue line moves up and down when there is exit and entry, respectively, because
A) the market demand for the good rises and falls when there is exit and entry, respectively.
B) the market demand for the good rises and falls when there is entry and exit, respectively.
C) the market supply for the good rises and falls when there is exit and entry, respectively.
D) the market supply for the good rises and falls when there is entry and exit, respectively.