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.  In hopes of gaining some indication of the fragments' size, astronomers studied spectrographic analyses of Jupiter's outer atmosphere.  These analyses revealed unprecedented traces of sulfur after the fragments' entry. The fragments themselves almost certainly contained no sulfur, but many 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?

(A) The first presents a circumstance for which the astronomer offers an explanation; the second is part of that explanation.

(B) The first acknowledges a consideration that weighs against the conclusion of the argument; the second is that conclusion.

(C) The first acknowledges a consideration that weighs against the conclusion of the argument; the second provides evidence in support of that conclusion.

(D) The first provides evidence in support of the conclusion of the argument; the second acknowledges a consideration that weighs against that conclusion.

(E) The first is a judgment advanced in support of the conclusion of the argument; the second is that conclusion.

正确答案是E，但是文章总是读得别扭，哪位NN能够把文章的逻辑分析一下么？ 在此谢过~

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.  In hopes of gaining some indication of the fragments' size, astronomers studied spectrographic analyses of Jupiter's outer atmosphere.  These analyses revealed unprecedented traces of sulfur after the fragments' entry. 介绍全文探讨的circumstance。

The fragments themselves almost certainly contained no sulfur, but many astronomers believe that the cloud layer below Jupiter's outer atmosphere does contain sulfur. 如答案所说a judgment advanced in support of the conclusion of the argument。

Since sulfur would have seeped into the outer atmosphere if comet fragments had penetrated this cloud layer, 因果关系的因为部分或者说是推理的一个前提条件，且承接上一句为接下来引出结论而做出铺垫。

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. 如答案所说本句为全文结论。

本文的逻辑架构基本如上所述，LZ加油。