Theancient Nubians inhabited an area in which typhus occurs, yet surprisingly fewof their skeletons show the usual evidence of this disease. The skeletons do show deposits oftetracycline, an antibiotic produced by a bacterium common in Nubian soil. This bacterium can flourish on the driedgrain used for making two staples of the Nubian diet, beer and bread. Thus, tetracycline in their food probablyexplains the low incidence of typhus among ancient Nubians.
Whichof the following is an assumption on which the argument relies?
A.Infectious diseases other than typhus to which the ancient Nubians were exposedare unaffected by tetracycline.
B.Tetracycline is not rendered ineffective as an antibiotic by exposure to theprocesses involved in making bread and beer.
C.Typhus cannot be transmitted by ingesting bread or beer contaminated with theinfectious agents of this disease.
D.Bread and beer were the only items in the diet of the ancient Nubians whichcould have contained tetracycline.
E.Typhus is generally fatal.
对于换库的一些想法：楼主由于水平不济，所以考G的次数不少，换库日，库中，加上这次库尾都考过了。发现这次这个题库和以前有些不同了。鉴于7月16日之后GMAT改革，GMAC说要在半月之内考试的同学尽量考到新题。楼主有以下两个猜想：
1. 库会变大：楼主看了刚刚的几个今天考试的帖子，有两位考生同一个考场，考的东西基本都不一样，难免让楼主认为GMAC把库变大了
2. 不再会有明显的换库日了：鉴于
