请大家帮我看看一道黑脸题gwd29-28

Astronomer:  Observations of the Shoemaker-Levi comet on its collision course with Jupiter showed that the comet broke into fragments before entering Jupiter’s atmosphere in 1994, but they did not show how big those fragments were.  Nevertheless, some indication of their size can be inferred from spectrographic analyses of Jupiter’s outer atmosphere.  After the fragments’ entry, these analyses revealed unprecedented traces of sulfur.
                 The fragments themselves almost certainly contained no sulfur, but astronomers believe that the cloud layer below Jupiter’s outer atmosphere does contain sulfur.  Since
                    sulfur would have seeped into the outer atmosphere if comet fragments had penetrated this cloud layer, it is likely that some of the fragments were at least large enough to have passed through Jupiter’s outer atmosphere without being burned up.

In the astronomer’s argument, the two portions in boldface play which of the following roles?

The first is a claim that the astronomer seeks to show is true; the second acknowledges a consideration that weighs against the truth of that claim.

The first is a claim that the astronomer seeks to show is true; the second provides evidence in support of the truth of that claim.

The first and the second are each considerations advanced in support of the conclusion of the argument.

The first provides evidence in support of the conclusion of the argument; the second is that conclusion.

The first is a circumstance for which the astronomer seeks to provide an explanation; the second acknowledges a consideration that weighs against the explanation provided by the astronomer.

 我选了E,当时选不出来,就猜了一个E,答案是C
我做黑脸题一向很好,结果栽在它手上了......
这题真的不太明白,特别是第一个加黑的句子

选E。

第一句是EVIDENCE，实实在在的EVIDENCE，没错。

第二局是一个CONSIDERATION，用来衡量天文学家发现的。这不能笼统说是EVIDENCE,应该说是一个理论，经验等等，这根第一句的EVIDENCE是有区别的，因为EVIDENCE必须是直接从该事件中提取出来的。第二局不是该事件的发现，所以不能算EVIDENCE。