求教一道语法题~

271632852

The first English settlers to establish a permanent colony in America did it not at Plymouth but along the shore of the James River west of Chesapeake Bay.



A.      it not at Plymouth but

B.       so not at Plymouth but

C.      not at Plymouth but instead

D.      not at Plymouth but did so

E.       it not at Plymouth but rather 看到有解析说这里的so指代动作，did不就指代了establish这个动作，it就指代colony么，这样不对么？
谢谢大家帮忙啦~~~~