I know this because A states that the training is not worth the cost, which is correct a little, but it does not state the right way. B is the wrong way around, and C is not even relavent to the text. Therefore you can conclude that D is correct. I JUST WANT THE RIGHT ANSWER TO BE IN THIS!
This quote can be found only in the movie. It can be heard in the third movie, and is told by the headmaster. I just checked the book, and it doesn't appear there.
