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: answer calls, file, correspondence, document, fax
document

Category: ocean 
Words: current, data sets, main, sea, wave
data sets

Category: poker 
Words: fold, check, hearts, deck, rudder

rudder