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: PUBLISHING
Clue: Founded in 1856, this company introduced a numbering system for U.S. highways in 1917

Answer: rand mcnally

Question: Category: HISTORIC NAMES
Clue: 2 of the people who witnessed his execution were John Wilkes Booth & Stonewall Jackson

Answer: john brown

Question: Category: 20th CENTURY WEDDINGS
Clue: Her 1956 wedding attracted more than 1,500 news reporters to a country with just 20,000 citizens at the time

Answer:
grace kelly