In the major cities of industrialized countries at the end of the nineteenth century, important public places such as theaters, restaurants, 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) electricity was in less than one percent of homes, where lighting was still -- Correct Answer. Proper verb used to differntiate between two different times. By end of nineteenth century, public places had lighting installed( was already in place before the time auther is talking abt) but homes were still using candles and gas (simeple past tense for the second event whoch was true at that time)
(B) electricity was in less than one percent of homes and lighting still - Incorrect - "and" is not neede here and changes the meaning
(C) there were less than one percent of homes with electricity, where lighting was still being -- Incorrect where lighting.. last part is modyfying electricity but should modify homes
(D) there was less than one percent of homes that had electricity, having lighting that was still -- Incorrect Modifier issue as (C)
(E) less than one percent of homes had electricity, where lighting had still been -- Incorrect. This answer suggests that only 1% of homes had electricity and situation must have changed by end of nineteeth century.