I voted for Big Boss, but the votes may become even so here's some written support.
Every time I've ever played Legend of Zelda, a character gives Link hints on how to beat the final boss.
If the player has no knowledge of how to do this prior to the encounter, either the player has dumb luck or he dies a few times before consulting the web. In Oracle of Seasons/Ages, it was these guys:
Here's a familiar face that also has a problem with Gohma, but from a different game:
Sheikah stones give advice and sometimes it is how to defeat bosses and they're in just about every game:
It fits the video games's narrative that Link would need help from the owls, old man, statues, deku scrubs, stones, etc. Otherwise why would they be so easily accessible? I actually enjoy the Zelda games more knowing Link isn't some infallible, "I've Got A Weapon For That" Marty Stu Hero's Journey trope, but a kid who gets help from the people, animals, and magical objects of Hyrule/Termina/Elsewhere in order to beat the big bad monster at the end of the temple. He gets these in every game he's featured in. But he doesn't have them here to help him.
So either he wins by dumb luck, running around shooting arrows or whatever at some guy not of his time with weapons he has never seen in hopes it would be effective, or he is about to eat bullets. I believe it would be the latter.