41. Under a provision of the Constitution that was never applied. Congress has been required to call a conven­tion for considering possible amendments to the document when formally asked to do it by the legisla­tures of two-thirds of the states.

(A)  was never applied, Congress has been required to call a convention for considering possible amendments to the document when formally asked to do it

(B)   was never applied, there has been a requirement that Congress call a convention for consider­ation of possible amendments to the document when asked to do it formally

(C)  was never applied, whereby Congress is required to call a convention for considering possible amendments to the document when asked to do it formally

(D)  has never been applied, whereby Congress is required to call a convention to consider possible amendments to the document when formally asked to do so

(E)   has never been applied. Congress is required to call a convention to consider possible amend­ments to the document when formally asked to do so

对答案和OG的解释都没什么问题，因为前两天的问题一直没解决，很关注状语从句省略主语和BE动词的情况，我查了语法书，上面说省略的主语就是主句主语。之前我问了OG11-68题，关于while引起的从句的省略，现在我对本题E答案有点不明白，asked 的主语是谁？Congress还是convention? 如果从语法结构来讲，应该是Congress吧，但从逻辑上来讲又好像是convention

现在发现这个语法点我一直就没搞明白过，大家来看看，帮我解决一下吧

do so --发出动作者和主语相同,这题的主语是Congress,所以是Congress

do it --发出动作者和主语不同