Who should I bench for a Dragon?

So yeah, this is my current team. I've just defeated Claire and I want to train my Adamant, Extreme Speed Dratini for the E4 and post game.

Who should I bench for it?

So yeah, this is my current team. I've just defeated Claire and I want to train my Adamant, Extreme Speed Dratini for the E4 and post game.

Who should I bench for it?