instruction:
Given a category and a set of five words, find the word from the set that does not belong (i.e. is the least relevant) with the other words in the category. Words are separated by commas.
question:
Category: type of sandwich 
Words: clan, lettuce, bacon, club, submarine
answer:
clan


question:
Category: animal 
Words: train, fly, jump, leap, grasshopper
answer:
train


question:
Category: construction 
Words: crane, steam roller, digger, hoist, mallet
answer:

mallet