Reiner in titan form is defiantly the strongest titan in my opinion.
So far we have seen him rush into an army of titans and no one could penetrate him, he have a neck protection that he doesn't haft to focus on protecting and the armor is impossible to penetrate with swords.
He is so strong in that titan form so he is throwing other titans (12 - 15 m classes from what I see) in such a long range.
So no. I doubt that Levi have a chance agains him and defiantly not Annie. It may take a while since she is a better fighter than him (Reiner's armor is slowing him down) but there is no way that she is penetrating him. So I go ahead and say that Armored Titan is the strongest titan in my opinion. I believe only pure strength can defeat armored titan (like pulling off limbs of that titat)
Edit : If we mean Reiner vs Annie (Non Titan form) then I believe Annie.
He can't cut his nape so Levi can't kill him. Just a matter of time until Levi runs out of gas and Reiner kills him. As for Annie, it depends on whether she can cut his nape if she hardens her hand, if not then she can't take him out.
Not a chance for Levi, unless he can somehow manage to severe the joint muscles (not armored), but that would only give him a chance to run/slow reigner down because he can't actually kill him.