It is B because why would you need to ask where is the bathroom if you are familiar with it? That means he is lying, and did something else in the meantime, in this case he was the murderer.
Reading is good for you because you can expand your reading vocabulary you also get to know a lot of stuff if it is a non-fiction book.Some people enjoy reading books and it is good for them.
Yes, of course, if you have nose bleed and you didn't look, you wouldn't know. When you go outside with the nose bleed they will think, why are you so disgusting? Unless you want to be disgusting.