一道manhattan模考题 请指教

仙蒂瑞拉

Every year many people become ill because of airborne mold spores in their homes. After someone becomes ill, specialists are often hired to eradicate the mold. These specialists look in damp areas of the house, since mold is almost always found in places where there is substantial moisture. If one wishes to avoid mold poisoning, then, one should make sure to keep all internal plumbing in good condition to prevent leakage that could serve as a breeding ground for mold.

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

		Mold itself does not create moisture.
		Most homeowners know enough about plumbing to determine whether theirs is in good condition.
		Mold cannot grow in dry areas.
		No varieties of mold are harmless.
		Mold spores cannot be filtered from the air 做的时候就在AB之间犹豫，不知道选什么，有没有人可以帮忙解释一下A为什么对？B错在哪里？先谢谢了！

仙蒂瑞拉

谢谢prayer的解释，很清楚！现在看出B是irrelevant了。

aeoluseros

A is a typical answer to a causality-related question--denying the possibility of reversed causality.

prayer

CR in my words : Molds cause problem. Expert come and eradicate it. They look in moist places. So, to avoid mold, avoid moist places.
Assumption : Molds form in moist places

Mold itself does not create moisture.
Most homeowners know enough about plumbing to determine whether theirs is in good condition.
Mold cannot grow in dry areas.
No varieties of mold are harmless.
Mold spores cannot be filtered from the air.

Answer = A. Because if mold themselves create moisture, then conclusion fails.
B - Third party - Eliminate. This is wrong because it is not necessary that they themselves know. They can ask others experts to ensure plumbing is in good condition.
C - Eliminate - This is not assumption, this is conclusion.... Tricky though.....
D - Third party - Eliminate
E - Out of scope - Eliminate
Answer A.