OG13-cr25，不明白C选项的解释意义何在，求助~~感谢ing

lionsue

请问OG关于c选项的解释到底要表达什么意思？
以前看这题的时候就一直疙疙瘩瘩没完全按解决，为了把握OG的思路，这次还是想再问问。。
思考良久，未果。。期待详细分析~~~

至于C项被排除的原因我的理解是：
1.树叶的功效与题中所提的树皮制药无关。
2.a number of medical products指的也非树皮制的那种药。

但OG对于C的错因是什么意思？尤其不明白的是If this information were provided, it would weaken support for the conclusion.这里指的的是什么信息？如果是指C项所说的树叶制药这个信息那么不是矛盾了么，本来C项就是提供了这个信息啊。

tanks a lot~~~

25. A drug that is highly effective in treating many types of infection can, at present, be obtained only from the bark of the ibora, a tree that is quite rare in the wild. It takes the bark of 5,000 trees to make one kilogram of the drug. It follows, therefore, that continued production of the drug must inevitably lead to the ibora’s extinction.

Which of the following, if true, most seriously weakens the argument above?

(A) The drug made from ibora bark is dispensed to doctors from a central authority.

(B) The drug made from ibora bark is expensive to produce.

(C) The leaves of the ibora are used in a number of medical products.

(D) The ibora can be propagated from cuttings and grown under cultivation.

(E) The ibora generally grows in largely inaccessible places.

Argument Evaluation

Situation The extinction of the rare ibora tree is inevitable if production of an effective infection-fighting drug continues.

Reasoning Which point most weakens the argument? The production of the drug requires such an enormous amount of bark that, the argument concludes, the continuing existence of the rare tree is in jeopardy. But the argument assumes that killing the trees in the wild is the only way to obtain the needed bark. Can the tree be cultivated? If so, the majority of the trees in the wild could be left to flourish.

A The method of the drug’s distribution is irrelevant, unless the central authority can limit the drug’s production from the bark of wild ibora trees. But this information is not provided.

B The cost of producing the drug does not affect the outcome for the tree unless it deters production.

C The existence of uses for other parts of the tree opens the possibility that the ibora-bark drug would cause no increase in destruction of trees other than what exists already. If this information were provided, it would weaken support for the conclusion. Since it is not provided, this option does not significantly weaken the argument.

D Correct. This information most weakens the argument.

E Difficulty of access to the trees could provide a disincentive to their harvesting—but we are not told that it would prevent their harvesting.