Once the supper table was cleared, the dishes washed, and the flowers in the garden watered, my grandparents would set to work on the Novels for You Reading Pleasure and Entertainment series. They worked at the dining table, pulling the ceiling lamp down and reading and editing the manuscripts, the page proofs, and the bound galleys. Sometimes they did some writing as well: they insisted that each volume conclude with a brief didactic essay, and when none was forthcoming they supplied it themselves. They wrote about the importance of toothbrushing, the battle against snoring, the principles of beekeeping, the history of the postal system. They also rewrote passages in the novels when they found them awkward, unbelievable, or immodest or when they felt they could make a better point. The publisher gave them a hand. (From and ACT reading passage)
Is "none" in this case meaning "all volumes were without a brief didactic essay provided” ?
Or is it indicating only occasional volume didn't conclude with a brief didactic essay?
I prefer the former one since I think that's essentially what "none" literally mean. But I ask this because the correct answer of a question approach "none" in the latter way:
The correct answer is H, but I prefer G instead