The ancient Nubians inhabited an area in which typhus occurred, yet surprisingly few of their skeletons show the usual evidence of this disease.  The skeletons do show deposits of tetracycline, an antibiotic produced by a bacterium common in Nubian soil.  This bacterium can flourish on the dried grain used for making two staples of the Nubian diet, beer and bread.  Thus, tetracycline in their food probably explains the low incidence of typhus among ancient Nubians.

Which of the following is an assumption on which the argument relies?

A.        The tetracycline deposits did not form after the bodies were buried.

B.        The diseases other than typhus to which the ancient Nubians were exposed would not be affected by tetracycline.

C.        Typhus is generally fatal.

D.       Nubian grain became contaminated with tetracycline-producing bacteria prior to being harvested.

E.        Bread and beer were the only foods eaten by the ancient Nubians which could have contained tetracycline.

此题答案为A(B),可是我怎么觉得5个没个好的呢，请各位指教阿~~~~

（此题与GWD-18-30很相似，但是那题的选项很清楚的，可以参考下）

文章的论证逻辑是，食物里含有此抗生素，而人体内也有该抗生素（因为skeleton里有），所以该抗生素对typhus有用。

A就是填补skeleton里有和体内有的gap。所以A对。

E说只有此二中食物中有该抗生素，这个是无关的。即使是其他的食物中也有此抗生素也不影响该推理。所以E错。

yeah~ I totally get it now.

thank you so much~~~