Use the following given market-for-money diagrams to answer the next question.Curve D1 represents the

When an airline reduces its fares, other airlines typically match the action. But when an airline increases its fare, other airlines do not follow suit. Which oligopoly model cartel, price leadership, or kinked demand best fits the airline industry as described? Justify your choice and explain why the other models are less appropriate

A consumer is maximizing utility when

A. the consumer has spent all of his income. B. the slope of the budget constraint has reached -1. C. diminishing marginal utility has set in. D. the slope of the budget constraint equals the marginal rate of substitution.