Honestly I don't think it will be either one of them, but IF it would be, I would have to say Damon. I think Stefan would let her make her own decision about turning or dying, but Damon would be the one to never let her die, even if that means turning her into a vampire by giving her the human blood to complete the transition. Yesyes, she's still "dead" but not dead dead, and ofc Stefan don't want her to die, and neither does Damon, they just have different ways to act, think, and handle situations.
That's just what I think.

stupid question both will.

Caroline, haha.