The lowest-income fifth of the U.S. population ordinarily earns about 20 percent of the income.

Economic theory suggests

A) social order is maintained only when people act in the public interest. B) as a rule, people cooperate more effectively when they're selfish compared to when they're generous. C) a great deal of effective cooperation can occur in the presence of minimal generosity and also without a great deal of government guidance and control. D) none of the above.

Which of the following is true if the total cost curve is rising?

a. Total fixed cost is decreasing. b. Total fixed cost is increasing. c. Marginal cost is decreasing. d. Marginal cost is increasing.