For many years, historians insisted that native American women in the 1800s adhered to a rigid vegetarian diet, including roots, nuts and berries. However, a recent study of their remains suggests that this might not be true. Hair samples from a Native American female revealed significant levels of Vitamin D and K, which the human body cannot produce on its own; further the only dietary source of these vitamins is red meat. Therefore, it is likely that Native American women from the 1800s consumed a meat-based diet, rather than vegetarian fare

Which of the following, if true, would strengthen this conclusion the most?

A.A recent nutritional study suggests that the human body can manufacture minute amounts of Vitamin D in frigid conditions.
B.The levels of Vitamin D and K in the hair samples from the Native American female were identical to those from women from Europe who eat a meat-based diet.
C.When the scientists re-ran the analyses on the same samples, they obtained identical results.
D.When scientists examined hair samples from the bodies of several other Native American women, they obtained identical results.
E.Twelve years after the scientists examined the hair samples and published their results, no one has disputed them.

OA and OE coming after some discussion.
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Kudos if it helped you in any way

I think the answer is B.

Promise: The only dietary source of these vitamins is red meat. Answer B supported that by stating people who eat a meat-based diet have similar levels of Vitamin D and K in the hair samples.

I think the answer is B because we are using other evidence from to support similar results that come from eating meat diets.

Whereas, answer D uses the same sample which is under question and cannot be used as comparison.

Yes D should be the answer.

I chose B. it is wrong, as the argument clearly mentions " further the only dietary source of these vitamins is red meat. ". So we shouldn't be looking for option which strengthens the argument - sources of these vitamin D and K is meat based diet. Rather we must strengthen the conclusion by looking for options which compares the result with other samples exactly what D does.

conclusion=Therefore, it is likely that Native American women from the 1800s consumed a meat-based diet, rather than vegetarian fare.
one of the premises talk about dietary source of vitamin D and K, but it does not tell us about Non dietary source.
B is not right because the level of vitamin D and K in the hair sample of European can be equal to Level of Vitamin D and K in the hair sample of American women, even though American women do not meat and one of the reason can be non dietary supplements.
Vitamin D source= Sun (a well known fact, even though not needed for answering the question)
Vitamin K source= Bacteria in the gastrointestinal tract( also not needed, but did some research out of curiosity)


Answer is D because it give us other evidence, which supports the conclusion.