B looks great! It's very dynamic, but it will be quite hard to handle all of the foreshortening. Personally I like A a lot. It's a bit more classical , but if you move the figure and the horizon line a bit higher, it would create this nice effect of "Ha! ha! I am superior!".
Also make sure that the viewer is looking at the rider and horse from the same angle. On the "A" picture, we can see the character from below, but the horse looks as if we look at it from the side or straight on.
Great work, keep it up