Explanation
Correct answer: B.
Choice B is the best answer because it presents a finding that, if true, would best account for the discrepancy Etta-Nkwelle observed: Asian countries showed evidence of herding (converging on the same foreign currency accumulation rate as their regional peers), while African countries did not. The text defines herding as individuals converging on the same action by imitating their peers, which implies that the individuals choose to do so rather than being compelled to follow a particular course of action. This choice indicates that most of the African countries belonged to economic unions that dictated such monetary policies, whereas Asian countries were free to choose, and the similarity among the Asian countries suggests that herding can account for that similarity. The finding thus identifies a relevant difference between the two regions that accounts for the discrepancy.
Why the other choices are wrong
Choice A
Choice A is incorrect. Although this choice is related to reserves of foreign currency, the fact that African and Asian countries had different mixes of foreign and domestic currency reserves does not address the rate of foreign currency accumulation or whether herding is a contributing factor determining the rate of accumulation.
Choice C
Choice C is incorrect. This choice does not address currency accumulation. And although it describes differences in the currency reserves of African and Asian countries shortly after the 1997 financial crisis, it does not address the rate of foreign currency accumulation nor how similar the nations were in this regard to their neighboring countries.
Choice D
Choice D is incorrect. Although this choice discusses the variety of foreign currencies accumulated by African countries as compared with Asian countries, it does not discuss the rate of foreign currency accumulation nor whether herding is a factor determining the rate of accumulation.