If any of those three somehow do it, it will be Nole though. He's the only one of those three who combines the game, mentality and fitness to have a chance to pull it off if he has a magical year and circumstances favor him. After all, he was relatively close in 2011 and Fedal have only gotten older.
Safe money is on nobody doing it though.
so has djokovic
he'll turn 26 next year, which for many great players before him (fed, nadal, borg) has been an age which marked a significant decline one way or another