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: support, fax, file, download, errands
download

Category: chocolate food 
Words: cake, fudge, rich, invent, cream
invent

Category: elements 
Words: flame, empower, fire, blaze, water

empower