CR old gmatpaper test Chanterelle

[gocoder]

The chanterelle, a type of wild mushroom, grows beneath host trees such as the Douglas fir, which provide it with necessary sugars. The underground filaments of chanterelles, which extract the sugars, in turn provide nutrients and water for their hosts. Because of this mutually beneficial relationship, harvesting the chanterelles growing beneath a Douglas fir seriously endangers the tree.
Which of the following, if true, casts the most doubt on the conclusion drawn above?
(A) The number of wild mushrooms harvested has increased in recent years.
(B) Chanterelles grow not only beneath Douglas firs but also beneath other host trees.
(C) Many types of wild mushrooms are found only in forests and cannot easily be grown elsewhere.
(D) The harvesting of wild mushrooms stimulates future growth of those mushrooms.
(E) Young Douglas fir seedlings die without the nutrients and water provided by chanterelle filaments.

Please correct me if my understanding is flawed. Is E incorrect because in a way it underscores the point discussed in the conclusion ?

[DavidG@VeritasPrep]

Please correct me if my understanding is flawed. Is E incorrect because in a way it underscores the point discussed in the conclusion ?

Yep. The conclusion is that harvesting the chanterelles will endanger the Douglas fir. In order to undermine that conclusion, we need to show that harvesting the chanterelles won't endanger the fir. The notion that the fir will die without the nutrients provided by the chanterelle simply shows that the chanterelles are integral to the fir's survival.