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.

Category: secretary duty 
Words: fax, program, file, make coffee, answer
program

Category: measurement unit 
Words: ounce, ear, inch, foot, milimeter
ear

Category: guitar part 
Words: pick, amp, fret, frustrated, strap lock

frustrated