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.

Q: Category: ANCIENT ROME 
Clue: This church faced periodic persecution for 300 years, until Constantine's conversion

A: christian church
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Q: Category: U.S. RIVERS 
Clue: The Falls of Saint Anthony stop this mighty river from being navigable north of St. Paul, Minnesota

A: the mississippi
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Q: Category: BLACK AMERICANS 
Clue: In 1965 these 2 Nobel Peace Prize winners participated in the Selma to Montgomery March

A:
martin luther king & ralph bunche
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