Black Americans are, on the whole, about twice as likely as White Americans to develop high blood pressure. This likelihood also holds for westernized Black Africans when compared to White Africans. Reseachers have hypothesized that this predisposition in westernized Black may reflect an interaction between western high-salt diets and genes that adapted to an environmental scarcity of salt. Which of the following statement about present-day, westernized Black Africans, if ture, would most tend to confirm the researchers' hypothesis? a. The blood pressure of those descended from people situated throughout their history in Senegal and Gambia, where salt was always available, are low. b. The unusually high salt consumption in certain areas of Africa represents a serious health problem. c. Because of their blood pressure levels, most White Africans have markedly decreased their salt consumption. d.Blood pressure are low among the Yoruba, who, thoughout their history, have been situated far inland from sources of sea salt and far south of Sahara salt mines. e. No significant differences in salt metabolism have been found between those people who have had salt availble throughout their history and those who have not. 请问这道题的逻辑关系是怎么样，我实在是读不懂，请大家赐教一下！ 参考答案：A | 
