Wraiths suck. Just a simple fact that you learn fairly early on in Halo: Combat Evolved Anniversary. So let's go hunting!
In this video, learn how to get the easy 'Wraith Hunter' achievement. All you need to do is take out four Wraiths on the level Assault on the Control Room using your Scorpion tank. That's it! No difficulty requirements, so you could even do this on Easy for 10G.