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: type of sandwich 
Words: grilled cheese, french toast, outing, burger, club

Answer: outing


Question: Category: nutritional value 
Words: sugar, calories, iron, fat, area

Answer: area


Question: Category: animal 
Words: iguana, dolphin, climbing, fish, horse

Answer:
climbing