Which of the following statements about the middle class in emerging economies is accurate?

a. Once known only for cheap labor, many countries with emerging economies are now seen as promising markets.

b. Estimates suggest that 20 percent of world growth over the next few years will come from emerging markets.

c. By 2030, two-thirds of the world’s middle class will reside in the United States.

d. Many countries such as China and India have become more suspicious of foreign investment and free trade.