Given a set of five words, generate the word from the set that does not belong (i.e. is the least relevant) with the other words. Words are separated by commas.

[Q]: fax, file, format, image, document
[A]: fax


[Q]: dog, goose, dodge, duck, cat
[A]: dodge


[Q]: concerted, united, synergy, rough, firm
[A]:
rough