Black Americans have high blood pressure twice as much as white Americans. The same is true of westernized blacks African compared to white Africans. Researchers hypothesize that westernized blacks suffer from high blood pressure for two reasons. The first is the high salt content of western foods; the second is the adaptation mechanism to the environment of the blacks' genes. Which of the following, if true, would best support researcher's hypothesis? ['Blood pressure in descendants of contemporary westernized black African Gambians is usually not high, as Gambians have historically been short of salt.', 'Unusually high salt intake in some parts of Africa is a serious health hazard.', 'Considering health, most white Africans also pay attention to controlling salt intake.', 'Salt deficiency and salt sufficiency have not found any substantial difference in human metabolism.']