Which of the following situations is in equilibrium?
A. Hundreds of people want to buy one of the 50 remaining copies of a rare book, so the 10 different booksellers with copies set up a lottery to decide which buyers will get copies.
B. At a grocery store there are three checkout counters. Counters 1 and 2 have lines of four people each, but no one is at Counter 3.
C. Every day at the fish market, the price of fish adjusts so that some purchaser buys every fish that is unloaded from the fishing boats.
D. There are two vending machines down the hall. One machine sells sodas for $0.50 per can, while the other sells sodas for $0.75 per can. Everyone lines up at the machine that sells at a lower price.
Help is greatly appreciated.. Thanks.