Geography is probably the most specific, followed by History. In Geography you have to know each of the main topics in detail and case study information you've done.
From what I've heard Science is also general knowledge of all topics from the last 2 years, which makes me worried because I've had very poor teachers for Science during this time e.g Absolutely no mention of the Watson-Crick DNA model in class, yet it appears as a question in the multiple choice in every second paper. I've learnt what it is now, but I'm worried about other topics like this.