1. In June of 1989, Princeton Township approved a developer’s plans to build 300 houses on a large portion of the 210-acre site of the Battle of Princeton, one of only eight Revolutionary War battlefields that had remained undeveloped.

(A) one of only eight Revolutionary War battlefields that had remained undeveloped

(B) one of eight of the only Revolutionary War battlefields that have remained undeveloped

(C) one of the only eight undeveloped Revolutionary War battlefields that remains

(D) only one of eight Revolutionary War battlefields to remain undeveloped（A）

(E) only one of the eight remaining undeveloped Revolutionary War battlefields

我是根据only的位置来判断选A，可是我仍是不太明白，各位能否帮我详细解释下？谢谢！