Which of the following are examples of Pareto-efficient changes? Explain your answers.
a. Cindy trades her laptop computer to Bob for his old car.
b. Competition is introduced into the electric industry, and electricity rates drop. A study shows that benefits to consumers are larger than the lost monopoly profits.
c. A high tax on wool sweaters deters buyers. The tax is repealed.
d. A federal government agency is reformed, and costs are cut 23 percent with no loss of service quality.