OG12 CR89 题目结构的问题，究竟谁是conclusion？（已解决）

Since it has become known that several of a bank’s top executives have been buying shares in their own bank, the bank’s depositors, who had been worried by rumors that the bank faced impending financial collapse, have been greatly relieved.  They reason that since top executives evidently have faith in the bank’s financial soundness, those worrisome rumors must be false.  They might well be overoptimistic, however since corporate executives have sometimes bought shares in their own company in a calculated attempt to dispel negative rumors about the company’s health.
In the argument given, the two boldfaced portions play which of the following roles?

(A) The first describes evidence that has been taken as supporting a conclusion; the second gives a reason for questioning that support.
(B) The first describes evidence that has been taken as supporting a conclusion; the second states a contrary conclusion that is the main conclusion of the argument.
(C) The first provides evidence in support of the main conclusion of the argument; the second states that conclusion.
(D) The fi rst describes the circumstance that the argument as a whole seeks to explain; the second gives the
explanation that the argument seeks to establish.
(E) The fi rst describes the circumstance that the argument as a whole seeks to explain; the second provides evidence in support of the explanation that the argument seeks to establish.

看了所有有关这道题的帖子，看来究竟谁是conclusion好像纠结的人还挺多。我看到有个帖子里面有人对于这题的结构有两种理解：
理解一：
文章先讲了一个事实several of a bank's top executives have been buying shares in their own bank,推理出结论：overoptimistic,第二黑体解释了结论
理解二：
文章先讲了一个事实several of a bank's top executives have been buying shares in their own bank,得出结论：银行经济状况好，随后作者质疑这种结论，认为过分乐观，第二划线部门解释了质疑理由

照CD解释，应该是理解二正确。但是，OG CR题目怎么有这种结构呢？CR的题目conclusion的定义是作者的观点，那么此题作者的观点是认为过于乐观。但是照“理解二”，作者的观点变成counterpoint了。。。
希望到家一起讨论下，把这道题的这个难点给彻底结束掉！

这道题我一开始也做错了。。。
不过LZ对文章的C不应该有疑问的
文章说：很多bank executives买自己银行的share，所以有个rumor就不攻自破了。然而，这样想的人都过于乐观，因为balabalabala...
LZ注意文章中有一个However，这是句间转折词，表示无论前面说了是什么，however后面才是作者的观点，而且肯定是跟前面不一样的观点。
however转折后的结论才是文章的结论，前面的部分知识为作者反驳描述背景，或通过对前面的反驳使得作者的conclusion更具有说服了。

所以结论应该是 They might well be overoptimistic，后面的BF是支持这个结论的
而第一个BF则是用来支持文章所反驳的结论

做完最后一个BF题目，第124题，恰好也是这种结构，有个fake conclusion的，现在彻底明白了。
不懂的可以把89和124两题结合起来。其实我觉得124题目结构更有助理解。