Other.Why? If any of those were the strongest,that would kill off the anime.And how can you say the 4th is the strongest when you haven't seen him in action.Your only judging that because he sealed Kyuubi he is the strongest.All hokages have access to the scroll with that jutsu and any of them could do what he done.You can't prove he is the strongest,no one can because he hasn't been shown enough anywhere for anyone to say that.