Answer:
Step-by-step explanation:
I think the answer is that the author wants to emphasize that the facts quoted from the book should be taken seriously. You means a specific listener is having a lecture made to him.
Narrowing it does from these choices is very hard because all 4 contain truth for using the pronoun you.
So I wouldn't choose A. You has more to do with the listener than the question. It is more what the writer wants the listener to know as a fact.
B: is true. The author wants the listener to pay attention.
C is wrong in the same way A is.
D the problem is that B and D are saying much the same thing. But the wrong person is used to accomplish the intent
Answer: B