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: THE COMPUTER AGE 
Clue: Dan Bricklin developed VISICALC, the first of these programs, similar to an accounting ledger

Answer: spreadsheet


Question: Category: SCIENCE & NATURE 
Clue: Developed by astronomer A.E. Douglass, dendrochronology determines age in this way

Answer: counting tree rings


Question: Category: THE AMERICAN REVOLUTION 
Clue: A staff officer for Frederick the Great, he came to fight after meeting Franklin in France

Answer:
baron von steuben