Do option A. Nature Rune prices have been going up and down for the past couple of weeks. You have lots of places to sell them except the RS official forums. You can use these forums to sell some, World 2, or just go to Edgeville in a busy world, worked for me and sold like 10,000 for 300ea in a short period of time. Take yews as an example, they went down a bit and came back up shortly after. 200k natures will get you a lot of cash even if the price drops to 280-295ea. So i think you should go for A : P.S. Gratz on the Herblore levels :)