Jinx, kalista, graves or cait

Jinx, 100%. She's good in literally every matchup. Supports can still swing the lane into a loss, but not as hard as with Graves.

http://i.imgur.com/TA1NHhU.png?1

Jinx is currently best ADC right now.

if you need an adc to be solid in lane and the enemies best tank is 1 or 2 bruisers cait will serve you well.

if the enemy if full of squishy targets graves is the adc to burst them down fast.

if the enemy if full of heavy tanks jinx will shred them fast after she scales out of lane.

kalista is one that you usually need a duo partner to trust your game play. her builds are versetile from single target crit to spread shot no crit.

Jinx Graves Cait

In that order.

Dont play Kalista without a duo unless you are insanely good with her.