Snorlax

93 IV its versatile enough to be a attacker and defender.

I would continue to power up the 80% IV Zen-Body Slam, as its max CP is around 3250 at Pokémon level 39 and the moveset is perfect. You're basically talking about trading 25-30 max CP between that and the 93% Snorlax but downgrading to the 4th best Defense moveset.

I would eventually power up the 93 L/BS one, too. But if you only have the candy for one, it's gotta be the ZH-BS one right now.

I'd power up all 3. The order in which you do it depends on the level you need to get a good spot in local gyms, If the first one is already doing a decent job work on the 2nd first.

I'd go with the 2455CP 80IV ZH/HB if you're looking for a defender. If a high level snorlax attacker (wouldnt get as much xp when you prestige) then obviously go with the 93% one.