Soldier (Rifles, MGs etc), these could include Scar Light, M60, RPK, AK-47.
Scout (SMGs, Pistols, Shotguns etc), these could include SPAS, XM1014, M9, Anaconda, MP5, K1A.
Sniper (Sniper Rifles), these could include AWM, Dragunov, PSG.
Assassin (Melee, Grenades, Pistols), these could include Knife, Shovel, Soccer Grenade, Anaconda, D Eagle.
Elite, this is achieved once you have obtained all of one class.