Character Role Analysis
This one's a bit less clear-cut, because there's some pretty compelling reasons to consider Jack's mom and Bunny as at least guides. For example, Jack's mom is a good role model for responsibility (she pretty much single-handedly takes care of their family), and Bunny leads Jack into being more courageous.
But, we come down on Miss Volker's side here. For one thing, Jack's hobby is history, and Miss Volker nurtures his interest. She also teaches him about responsibility, duty, and appreciating where he comes from. Finally, she teaches him the most important lesson: to remember his history so he doesn't keep doing stupid things.