In a perfectly competitive market

A. Price exceeds marginal revenue for each unit sold
B. Average revenue exceeds marginal revenue for each unit sold
C. Administrative barriers can make it difficult for firms to enter an industry
D. No seller can influence the price of the prduct

Google started as one of many internet search engines, amazon started as an online book seller, and ebay began as a site where people could sell used personal items in auctions. these firms have grown to be so large and dominant that they are facing antitrust scrutiny from competition regulators in the us and elsewhere. did these online giants grow by fairly beating competition, or did they use unfair advantages? are there any clouds on the horizon for these firms -- could they face diseconomies of scale or diseconomies of scope as they continue to grow? if so, what factors may limit their continued growth?

White truffles are a very prized and rare edible fungus that grow naturally in the countryside near alba, italy. suppose that it costs $200 per day to search for white truffles. on an average day, the total number of white truffles (t) found in alba is t = 20x − x 2 , where x is the number of people searching for white truffles on that day. white truffles can be sold for $100 each. if there is no regulation, how many more people will be searching for white truffles than the socially optimal number?

The third program provides families with $50 in food stamps each week, redeemable for both perishable and nonperishable food. the fourth policy instead provides a family with a box of nonperishable foods each week, worth $50. use two graphs to illustrate that a family may be indifferent between the two programs, but will never prefer the $50 box of nonperishable foods over the $50 in food stamps. state your answer and use a consumer choice model for perishable food and nonperishable food to graphically justify your choice.