请教PREP2-11-Q38 ！！

小奇奇怪lily

Most farmers attempting to control slugs and snails turn to baited slug poison, or molluscicide, which usually consists of a bran pellet containing either methiocarb or metaldehyde.  Both chemicals are neurotoxins that disrupt that part of the brain charged with making the mouth move in a coordinated fashion--the "central pattern generator"--as the slug feeds.  Thus, both neurotoxins, while somewhat effective, interfere with the slugs' feeding behavior and limit their ingestion of the poison, increasing the probability that some will stop feeding before receiving a lethal dose.  Moreover, slugs are not the only consumers of these poisons:  methiocarb may be toxic to a variety of species, including varieties of worms, carabid beetles, and fish.
Researchers are experimenting with an alternative compound based on aluminum, which may solve these problems, but this may well have a limited future as we learn more about the hazards of aluminum in the environment.  For example, some researchers suggest that acid rain kills trees by mobilizing aluminum in the soil, while others have noted that the human disease Alzheimer's is more prevalent in areas where levels of aluminum in the soil are high.  With farmers losing as much as 20 percent of their crops to slugs and snails even after treatment with currently available molluscicides, there is considerable incentive for researchers to come up with better and environmentally safer solutions.
In the passage, the author is primarily concerned with

(A) describing the limitations of molluscicides that affect feeding behavior
(B) proposing alternatives to current methods of controlling slugs and snails
(C) emphasizing the need for an alternative to currently available molluscicides
(D) explaining how molluscicides are used to control slugs and snails
(E) criticizing the use of hazardous material for controlling slugs and snails
这个答案选项中的B和C，在读原文的过程中无法区分更符合两个中的哪一个，求牛牛们帮帮忙！

Jinny1840

斑竹glhelr的《阅读笔记》有讲解呀：
(B)    提出控制鼻涕虫和蜗牛的另一种方法。这个选项容易误选。作者确实提出了令一个方法，但是作者反驳了这个方法并在结尾说需要其他的方法，说明作者不是为了提出第二个方法才写的文章。
(C)    Correct. 强调现在的软体动物驱除药需要改变。其实作者一开篇就强调说现在的方法不好，进而说新的方法也不好，需要别的方法。所以作者的目的是要强调需要另外的方法。

小奇奇怪lily

万分感谢！我都不知道有这么本好书，解释的太好啦 谢谢你！