Which statement in the excerpt uses fallacious reasoning?

"we must blame parents in this matter rather than their children," because people's faults cannot be blamed on other people.

"if you would have your children grow up beloved and respected by their elders as well as their contemporaries, teach them good manners in their childhood," because the author says it without any proof.

"we must blame parents in this matter rather than their children," because the author has specifically discussed the schools' role, not the parents'.

"if you would have your children grow up beloved and respected by their elders as well as their contemporaries, teach them good manners in their childhood," because older people's opinion of younger people is not important.