【单选题】

Parents should stop blaming themselves because there’s not a lot they can do about it. I mean the teenager (十几岁的孩子) problem. Whatever you do or however you choose to deal with it, at certain times a wonderful, reasonable and helpful child will turn into a terrible animal.

I’ve seen friends deal with it in all kinds of different ways. One strict mother insisted that her son should stand up whenever anyone entered the room, open doors and shake hands like a gentleman. I saw him last week when I called rounD、Sprawling himself (懒散地躺) on the sofa in full length, he made no attempt to turn off the loud TV he was watching as I walked in, and his greeting was no more than a quick glance at me. His motherwas ashameD、"I don’t know what to do with him these days," she saiD、"He’s forgotten all the manners we taught him."
He hasn’t forgotten them. He’s just decided that he’s not going to use them. She confessed (坦白) that she would like to come up behind him and throw him down from the sofa onto the floor.
Another good friend of mine let her two daughters climb all over the furniture, reach across the table, stare at me and say, "I don’t like your dress; it’s ugly. " One of the daughters has recently been driven out of school. The other has left home.
"Where did we go wrong " her parents are now very saD、Probably nowhere much.At least, no more than the rest of that unfortunate parents.
What is the author’s opinion about the sudden change in teenage childrenA．Parents have no choice but to try to accept it.
B．Parents should pay still more attention to the change.
C．Parents should work more closely with school teachers.
D．Parents are at fault for the change in their children.