A consumer's indifference curves are right angles when, for the consumer, the goods in question are __________

GDP understates the value of output produced by an economy because it

A) includes environmental degradation caused by increased output production. B) includes transactions that do not take place in organized markets, such as home-cooked meals. C) excludes value added from the underground economy, such as tips taken "under the table." D) excludes the value of the wages and benefits of government employees.

A marginal benefit curve shows

A) the efficient use of resources. B) the quantity of one good that must be forgone to get more of another good. C) the quantity of one good that people are willing to forgo to get another unit of another good. D) there are increasing opportunity costs.