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: nervous, frustrated, fret, jack, concerned

A: jack
****
Q: sustainability, firm, amalgamated, combined, rigged

A: rigged
****
Q: elbow, foot, knee, inch, hand

A:
inch
****