Unscramble the letters in the given words to generate meaningful words. Three of the resulting words name an organised body of people; find the odd one out. POROT, WRCE, BMO, SALCS

Unscramble: POROT = TROOP, WRCE = CREW, BMO = MOB, SALCS = CLASS. A troop, a crew and a class are organised bodies of people with defined membership; a mob is a disorderly, unorganised crowd. So BMO (MOB) is the odd one out.