1. Naruto
He's holding on to it with his everything, down to his last breath, his last heart beat.
It was painful, losing someone who was the closest he's had to a brother. But, he's not lost forever. He can't be.
Because if he's gone forever, he'll fail so many promises he made to so many people. Sakura, Kakashi, Iruka, so many others. (Most weren't said aloud, just silently known to be there)
Besides, Orochimaru's creepy. Why would Sasuke want to work for him? (revengeandpainandhateandlonelinessmaybe?) It'll be easy.
Naruto's still believing there's a chance. He's clinging to it.
Because there's no way he's letting his (not-really) brother fall away.