in B, it's a ";" after the main sentence.
in D, is it ok to use such DU LI ZHU GE as "subject + prep. phrase", i.e. ten percent of them on the verge of ...?
justag:
1、I do choose B of question 3。In my last page,I just want to explain why I did not choose D
2、According to question 1, I agree with your opinion that the right expression is “not so as to”