提问]GMATPrep中一道语法题

In the major cities of industrialized countries at the end of 19th century, important public places such as theatres, shops, and banks had installed electric lighting, but electricity was in less than one percent of homes, where lighting was still provided mainly by candles or gas.

A. 如划线部分

B. less than one percent of homes had electricity, where lighting had still been

答案：A

为什么B不对？我感觉A读起来非常绕口，也不顺。

B. less than one percent of homes had electricity, where lighting had still been

===》非限定性定语从句 where 指向前面最近的名词 electricity, 错。

多谢！