I pick B because if areas of high salt consumption in Africa suffer health risks, then it explains why some Westernized black Africans would have health problems from eating too much salt.

1) Black Americans are twice as likely as White Americans to develop high blood pressure.

2) This likelihood also holds for westernized Black Africans when compared to White Africans.

3) Hypothesis: predisposition in westernized Blacks may reflect an interaction between western high-salt diets and genes that adapted to an environmental scarcity of salt. <-- hypothesis

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.
- Blood pressure of those descended from Africa was low. Contradicts the findings of the researchers.

(B) The unusually high salt consumption in certain areas of Africa represents a serious health problem.
- We can't be sure the serious health problem is high blood pressure. It could be kidney failure due to a high salt content diet.

(C) Because of their blood pressure levels, most White Africans have markedly decreased their salt consumption.
- Does not help the hypothesis by suggesting those from a traditional low salt diet will suffer high blood pressure when they move to a culture with a high salt diet.

(D) Blood pressures are low among the Yoruba, who, throughout their history, have been situated far inland from sources of sea salt and far south of Saharan salt mines.
- Blood pressure of African tribe is low due to scarcity of salt (meaning low salt diet). This supports the hypothesis of the researchers

(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
- Weakens the statement

D it is.

Took about 6 mins =(

Took about 5mins to choose D.

Half of that time i thought it shd be A. then i saw the "where salt was always available" statement in A which contradicts the scarcity position in the question stem.
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It's not over until it's OVER!

stem: high salt diet (westernized) + Gene adapted to low salt = HBP



high sale diet + Gene NOT adapted to low salt = NOT HBP

follow the logic of the stem



High salt diet + Gene adapted to low sale = low BP

Contradicted with the stem.

so I will choose A.

this question took me more than 7 mins, I have to write it out to understand the logic.