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: file, software, schedule, support, order office supplies
software

Category: chocolate food 
Words: fudge, chocolate cake, pudding, unwarranted, heavy
unwarranted

Category: animal 
Words: kayak, fish, whale, tiger, dolphin

kayak