问一道KAPLAN的逻辑题吧

冷泠UID: 2123335

怎么也没想通,或者是我理解错误?我把解释也贴上去了,望牛人指教!!!
6. A recent survey of American households casts doubt on the generally accepted
medical doctrine that psoriasis is transmitted genetically rather than through
interpersonal contact. In households including more than one person, and where
interpersonal contact is common, multiple cases of psoriasis were significantly
more frequent than the disease’s overall incidence would predict. Pending
further study, unnecessary contact with psoriasis sufferers should be avoided.

A logical critique of the passage above would most likely emphasize which of
the following?



6. logical criticism of the argument must emphasize the weakness of the
evidence: the interpretation of the study itself. Specifically, the study
doesn't indicate that the disease is transmitted interpersonally as it claims.
In multiple-person households where more than one person has the disease, it's
possible that these people are related to each other. If this is the case, then
the disease could have been transmitted genetically. The study isn't clear on
this point. The author hasn't considered family relationships among household
members (B).
(A)The flaw is in the assumption underlying the whole argument, not in one
particular phrase.
(C)Until more is known about multiple-person households, it makes no difference
what the overall incidence of the disease is.
(D)Ignores the issue of how psoriasis is transmitted and how it can be
contained.
(E)The direction of future study is beyond the scope.

stephanie_sisuUID: 201114

题目是探讨该疾病究竟是基因遗传还是接触传染
题目中的supporting evidence用了一个例子，同一屋檐下住了不止一个人的群体患该疾病的比例更高
于是题目就自说自话的给出了结论：接触传染
实际上，正如解释中所言，同一屋檐下住的人极有可能有血缘关系，即基因遗传的因素未被排除，所以无法得出题目中的结论
所以选B

冷泠UID: 2123335