Multiple choice Pick the odd one out. Elephants, walruses, bees, horses and wrens Elephants Walruses Bees Horses Wrens Reveal answer Fill a bubble to check yourself C Correct answer Explanation Correct. The common factor is the collective noun – herd – used with four of the five given options viz. elephants, walruses, horses and wrens. The odd one out is the word - bees. The collective noun for bees is – grist, hive or swarm.