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?

1. The first summarizes the evidence used in the reasoning called into question by the argument; the second states the counterevidence on which the argument relies.
2. The first summarizes the evidence used in the reasoning called into question by the argument; the second is an intermediate conclusion supported by that evidence.
3. The first is an intermediate conclusion that forms part of the reasoning called into question by the argument; the second is evidence that undermines the support for this intermediate conclusion.
4. The first is an intermediate conclusion that forms part of the reasoning called into question by the argument; the second is the main conclusion of the argument.
5. The first is an intermediate conclusion that forms part of the reasoning called into question by the argument; the second states a further conclusion supported by this intermediate conclusion.

给出的答案选d,个人对intermediate conclusion去形容since....不太明白,since接的能表示结论么,不解

答案是d我知道,就是不太明白since....能作为一个intermidiate conclusion么，since接的应该是表示原因的吧,这里的intermidiate conclusion该如何理解