It definately wont be jekyll, that was in my exam last year. It might be about setting or the gothic theme throughout the novel. It probably won't be utterson because you don't really get that much information about him apart from him being 'austere'. You see pretty much everything through utterson's pov and RLS dosen't reveal much about him since utterson is trying to uncover the secrets of Hyde throughout the novel. It could be about utterson's perspective, I find it hard to see that there could be a question about utterson as a character though.