Ok depending on where you live, legally, none. If you are however, allowed to run a spacer, you shouldn't run more than one on each wheel. The best spacer you can run is a hubcentric bolt on spacer, it uses your factory studs to bolt on to the hub then have it's own studs pressed in to it to mount the wheel. The ones I use are H&R, 25mm, and they are really good.
If you don't use that type you will be using one that simply goes between your wheel and hub. It's important to get one that is hubcentric so it doesn't move, and also that you ensure your studs are long enough to ensure a good amount of thread is in the wheel nuts - you will likely need to run extended wheel studs.
Personally I don't like option B, but if you don't want to go out too far then you'll not be able to run one from option A, as it needs to be large enough to house the factory studs and nuts.