也来请教一道白勇语法题，请nn们指教

Where once the union had acquiesced to the prejudices of its English-speaking members by supporting the imposition of an alien tax on immigrant workers, after 1897 the United Mine Workers made a determined effort to enlist Italians and Slavs in its ranks.

(A) Where once the union had acquiesced to the prejudices of its English-speaking members by supporting

(B) Where once the union acquiesced to its Engilsh-speaking members' prejudice for the support of

(C) While once the union had acquiesced to the prejudices of its English-speaking members in support of

(D) While once the union acquiesced to its English-speaking members' prejudice in supporting

(E) While once the union had acquiesced to the prejudices of its English-speaking members in its supporting of

白勇解释：1、抓基本结构——Where（尽管）从句。

这里我觉得有点疑问，where是尽管从句吗？好像不对啊？

我查寻webster where的用法，没有找到尽管的意思。我的理解是 where表示一种状态，情况。相当于in a case, situation。不过联系下文，可以稍微体会到一点转折。

这里通过support排除吧。 根据习惯用法排除BDE。

By supporting 和 in support of 语法上都可以。但是，这里的逻辑意思“通过什么”来达到那个目的。逻辑主语是 unions

in support of 倾向于 支持的意思。同时，这里疑似修饰members。

所以排除。