Which of the following has been observed in the devel oping countries during 1990-2012 ? a. The dispersion in the growth rates of the developing countries has been negligible during 1990-2012 . b. The East Asian countries like South Korea, Singapore, and Taiwan reported negative growth rates. c. Countries like China and Vietnam reported positive but very low growth rates. d. Several of t he countries in Eastern Europe and Central Asia that were making a transition from centrally planning to market-based economy reported a decline in the per capita income.