【之前没有讨论的一个知识点】TTGWD4-Q17

Q15: TTGWD4-Q17: B

The steel industry has changed radically over the last two decades, as large, integrated companies such as Bethlehem Steel once conducted operations from mining at one end of the process to shipping at the other have greatly downsized, or in some cases shut down altogether.

as 引导的是一个原因状语从句，表示因为。

A.  as large, integrated companies such as Bethlehem Steel  缺少that，使得从句的conducted变成主语谓语

B.  as large, integrated companies, such as Bethlehem Steel, that

C.  with large, integrated companies, such as Bethlehem Steel, that

D.  ！while large, integrated companies, such as Bethlehem Steel, that   while表示对比，改变了句子意思

E.   and large, integrated companies such as Bethlehem Steel

答案选B，我选了D，对于B我没有疑问了，想请教一下NN，是不是D的错误如我总结的，表示原因的变成了表示对比的，改变了句子意思？谢谢。