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.
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Question: Category: secretary duty 
Words: answer calls, file, correspondence, document, fax

Answer: document


Question: Category: nutritional value 
Words: vitamin c, salt, sugar, fat, big boned

Answer: big boned


Question: Category: baby animals 
Words: hatchling, buck, woods, fawn, lust

Answer:
lust