Apologies for bumping an old thread. But I have gone through the previous discussion and I didn't find useful information.
In choice A, it says
but electricity was in less than one percent of homes, where lighting was still provided mainly by candles or gas.
I chose B because I think that where represents the "homes" and isn't like 99% homes where lighting was still provided mainly by candle or gas, not the whole homes?
I am not here to question the official answer, just trying to figure out why. It is really hard for a non-native speaker to understand.
Thanks in advance.