1st question
B: The whole article talks about the "threats" posed by adolescents, it is highly persuasive in saying how bad we are, not if adults can tolerate us
2nd Question
2nd and 3rd sentence in the 3rd paragraph outline answers A and B, whereas C is the opposite to what they're saying
3rd Question
It sounds as though it is written by a parent, hence the "author's point of view" is going to be on the side of the parents, and against the children.
A: Adolescents are useless, annoying etc, not compassionate
B: "They threaten EXISTING arrangements"
C: Parents used to be good, these days though adolescents are useless
D: "dropping what they had yearned" - sympathetic to the parents
For the last question:
I agree with you, because "most are lower = some are higher", but I spose it's debatable as to whether "most" is a higher probability than "some"?
Hopefully this helps