求助？？？？885大全SECTION B-13

13.  After the Vietnam war Bettye Granther, a U.S. Army nurse, continued her efforts on behalf of injured Vietnamese children, providing medical care, helping to reunite estranged families, and the establishment of a fund for the children’s future education.

(A) the establishment of a fund for the children’s future education

(B) the establishing of a fund for the future education of children

(C) establishing a fund for the children’s future education

(D) establishing a fund for the childrens’ future education（C）

(E) the establishment of a fund for the childrens’ future education.d

为什么选C不是D，children’s future education区别是什么？？？？？？？？？？

                              childrens’ future education

                              childrens’ future education