Levon Aronian

If he can perform well in the candidates tournament this will be his best chance to beat Magnus.

Can Aronian hold his form long enough ?

Aronian will probably start having his brain farts in the candidates, unfortunately.  His play style poses the most problems for Carlsen but I think Aronian has Ivanchuk-syndrome.  I'll be rooting for Aronian and Mamedyarov in the candidates (I have faith that Mamedyarov will qualify via FIDE GP), those two are my favorite current players.  

Essentially, Aronian will beat Carlsen when Aronian can beat Aronian.

I think the OP was talking about the candidates Broccoli, not the tournament he is in now.

Levon has played great this year but he notoriously blows up in candidates tournaments. Perhaps this time he will hold it together. Will be interesting to see how Ding performs also. Probably roughly equal chances for all the guys involved to win it.

as for being a troll Broccoli, you're pathetic.

Karjakin played a bad match, if we're talking the one vs Carlsen. He tried to draw every game (how can you win like this? and even if you do, are you a good champion?), and more importantly he was getting slightly outplayed in most games. Carlsen had good winning chances that ended up as draws.

Then Karjakin got lukcy, Carlsen messed up and gifted his opponent a win. At that point it seemed Karjakin may even win the match because there were so few games left, but Carlsen won a game anyway and then won in the playoff.

The match score was close, but it was always Carlsen's match to win or lose.

At the time Karjakin was barely in the top 10. After the match, and presently, he fell just outside of the top 10. Not a good challenger or champion IMO (although of course a super world class player, just not the #1 player).

Aronian too weak, too slow

if you reattach those wires to your brain, it might start working again Brocc.