The first answer I don't really agree with but if I did the detail I would choose is: Laurie thinks he is better than Charles because he talks down about him. Because when he comes home he is always so excited to tell his parents what Charles did but not what he did, so in a way Charles is kind of like Laurie's guinea pig to find out what his parents would do when they found out.

I think whoever wrote the second answer also chose good detail but they just didn't explain themselves. If I were them I would've said: Laurie is Charles because Laurie's mom said,"An era of my life was ended, sweet voiced nursery-school tot replacedby a long trousered swaggering character who forgot to stop at the corner and wave goodbye to me." This shows that Laurie is Charles because Laurie is giving his mom attitude like Charles did the teaher so you can tell he is starting to act unpleasant.