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.

Researchers have hypothesized that this predisposition in westernized Blacks may reflect an interaction between western high-salt diets and genes that adapted to an environmental scarcity of salt.

Which of the following statements about present-day, westernized Black Africans, if true, would most tend to confirm the researchersтАЩ 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 among 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.

Well... an interesting question.
As for me I was struggling between B and E, but chose E. Here's my thoughts:
Imo A is incorrect.
The blood pressures of those descended from peoples situated throughout their history in Senegal and Gambia, where salt was always available, are low. First of all, I do not like those explicit geografical pointers (Senegal and Gambia). Next, the argument talks about hypothising that Black Americans are coming from regions with scarce salt. But Choice A offers quite oppisite facts. Out of the Scope.

B. The same story. This answer choice suggests "certain areas of Africa" as a reference point. We are analysing the Black Africans in general, "certain areas" are deceptive.

C is tempting, but how can we be sure that it assumes HIGH blood pressure, but not LOW?

D is tempting as well, but it doesn't bear on genes (I treat "genes" as Subject-specific qualifier).

E I took me quite a long time to land with this choice, but look: if we know that both groups of people have similar salt methabolism level, we may conclude that even if there are different levels of salt consumption in both groups, African people organism itself produces sufficient level of salt. That gives us 100% proof that high salt American diets are killing for Black Africans, who thus expose temselves to high levels of salt inputs.

d_batra79
thanx, you are right