To the team opposite the troll player.
Honestly, I understand it is ranked and it is all about winning but its already 4v5, why make it 4v6 and feed into the troll? If he wants to stand in lane why not let him stand there, he is leaching XP already so why make the troll feel that what he is doing is working?
9/10 times (the 1 time being say placements to a new tier and it being my 5th game) if the enemy team has a troll I will let him run around and do whatever, I will act like he is not even there. I do not understand why players constantly kill the troll that has an intent to intentionally feed, it just makes him do the same thing the next game and the game after that.
So if the team you are playing has a troll, think about just letting him sit there rather than feeding into what he wants to do.