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

Which of the following, if true, mostseriously weakens the argument above?

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

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

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

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

(E) The ibora generally grows in largelyinaccessible places.

答案是D， 这个理解，很直接的削弱，不过对C的OG解释看不太懂。为了搞清OG 的思路就纠结着想看懂它对这个错误的选项到底想说什么。。。谢谢大家帮助解释哦~~

OG解释C：C Theexistence of uses for other parts of the tree opens the possibility that theibora-bark drug wouldcause no increase in destruction of trees other than what exists already. If this information wereprovided, it would weaken support for the conclusion. Since it is not provided,this option does not significantly weaken the argument.

不太清楚。