You will be given a trivia clue, and the category it belongs to. You should answer with the best answer that belongs in the category and is described by the clue. For simplicity, answers should be in all lower cased letters.
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Question: Category: SOUTH AMERICA 
Clue: Alphabetically, they're the first & last of the 7 countries where the Andes are found

Answer: argentina & venezuela


Question: Category: FINANCE HISTORY 
Clue: In the 19th c., selling stock you didn't yet own, hoping it would fall, was called selling this animal's skin

Answer: a bear


Question: Category: HISTORIC NAMES 
Clue: On June 27, 1525 he married former nun Katherine von Bora

Answer:
martin luther