求解一道逻辑题 [蓝书上第26页，第69题]

霏儿R

Black Amermicans are, on the whole, about twice as likely as White Americans to develope high blood pressure. This likelihood also holds for westernized Black Africans when compared to White Africans.
Researchers have hypothesized that this predisposition in westernized Blacks may reflect an interaction between western high-sailt diets and genes that adapted to an environment scarcity of salt.
Which of the following statements about present-day, westernized Black Africans, if true,would most tend to confirm the researchers' hypothesis？

（A) The blood pressures of those descended from peoples 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 pressures are low amont the Yoruba,who, throughout their history,have been situated far inland from sources of sea salt and far south of Saharan salt mines.
（E）No significant differences in salt metabolism have been found between those people who have had salt available throughout their history and those who have not.

sdcar2010

Answer A "The blood pressures of those descended from peoples situated throughout their history in Senegal and Gambia, where salt was always available,  are low", confirms that when their genes adapted to the abundance of salt, black and white Africans do not have high blood pressure. This finding removes the possibility that black Africans are genetically prone to have blood pressure regardless of the availability of salt in their diets for their ancestors.