von Thunen 1826, a German farmer. the model is based on transportation costs and location.
Johann Heinrich Von Thunen
Well obviously, they haven't announced that an we'll have to see in May. But if you go to the college board website, and look at past FRQs, you'll notice the questions recently have been about the von Thunen model, economic development, and migration. But then again, there hasn't been a Culture question in quite some time, so they might mix it up this year.