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, errands, type, folder, order office supplies
folder

Category: animal 
Words: hamster, mice, fish, tiger, row
row

Category: bird 
Words: flamingo, dump truck, derrick, duck, crane

dump truck