[求助]旧prep2，77

77.       (28625-!-item-!-188;#058&004000)

The Anasazi settlements at Chaco Canyon were built on a spectacular scale with more than 75 carefully engineered structures, of up to 600 rooms each, were connected by a complex regional system of roads.

(A) with more than 75 carefully engineered structures, of up to 600 rooms each, were

(B) with more than 75 carefully engineered structures, of up to 600 rooms each,

(C) of more than 75 carefully engineered structures of up to 600 rooms, each that had been

(D) of more than 75 carefully engineered structures of up to 600 rooms and with each

(E) of more than 75 carefully engineered structures of up to 600 rooms, each had been

 这题都有点不好意思问，，，，只能说自己语法底子太差了。。。。

谁能给说说这个of up的插入语，of跟谁走？是和structure么？