想来想去不明白。。。求助PREP118

aweofhwoeijf

118. The ancient Nubians inhabited an area in which typhus occurs, 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) Infectious diseases other than typhus to which the ancient Nubians were exposed are unaffected by tetracycline.
(B) Tetracycline is not rendered ineffective as an antibiotic by exposure to the processes involved in making bread and beer.
(C) Typhus cannot be transmitted by ingesting bread or beer contaminated with the infectious agents of this disease.
(D) Bread and beer were the only items in the diet of the ancient Nubians which could have contained tetracycline.
(E) Typhus is generally fatal.


求助一下！按照HELR的方法解题，这题属于相关-因果，B选项我理解。
C选项为何不行呢？C讲的是“当面包和酒（抗体）被致病原感染污染时，食用该面包和酒不会受Typhus感染”
这个不符合CQ1:在其他时间、地点下，A仍然导致B吗？