Working title Trady101

Well, I am thinking about my second now. What I had in mind for a while now is a Harry Potter (HP) cache but not the kind where its all about how good HP is. Now don’t get me wrong here, I really like that stuff and I guess I have listened to it more then most others. I even used it to learn danish (with little success so far). In any case, here are the ideas for the “riddle”.A) Which class is Harry Potter only attending once?B) How many points loses Hermione when she lies about why she is in the bathroom one Halloween? C) By which creature is Hermione nearly attacked in this bathroom?D) Why could HP not have found the Philosophers Stone? (e.g. get it out of the mirror)