In the first pic the angle under the chin has opened up a little, could probably open up more to be more text book perfect, the two grounded legs are matched and once in the same position as the third pic will probably match the front and hind leg action. So I would probably choose this one as the best, just at a different time.
The second pic the horse hasn't opened its noses out enough and hence the foreleg movement probably won't match the hind leg movement when it is in the same position as the third pic. Too much front, not enough back. Its face and neck seem rather held back.
The third pic the legs all match but the nose is still a little behind the vertical, they could definitely come forward there but nicely matched front and hind.