IT HAS TO BE AN ACE

AND HERE IS WHY -

It had to be an ace. Think about the possibilities. Fingers told us that there was at least one, maybe two or three aces. So, if there were one ace, that person would know immediately, because they could see two deuces. Yet nobody declared immediately so there had to be two or three aces. If there had been two aces, two players would have seen an ace and a deuce, right ? Having worked out that we definitely know there isn't just one, these players could have correctly worked out their cards as being an ace. But after a while, when no one has said anything it has to be the case that there are really three aces, because it is the only option left. Therefor your card must be the third ace.

Check it out with some cards if you like - then why not mystify your friends, or even better, your enemies !