9. The proposed urban development zones do not represent a new principle; it was employed in “Operation Bootstrap” in Puerto Rico.

(A) do not represent a new principle; it

(B) represent not a new principle, but one that

(C) are not a new principle; the same one

(D) are not a new principle, but one that

(E) are not new in principle; it

正确为B。 当时做的时候，我选了A， 觉得“do not represent a new principle"表达没有错误，但是这个错是不是错在分号后面的it指代错呢？ 选项B中的one是指前面的principle吗？

Yes, it's not clear what it refers to. Strictly speaking, "one" refers to a principle but not the "a new prnciple" in the first part of the sentence. It could have been written as "but a principle that" , but for the sake of being concise, the phrase is replaced with "one".