instruction:
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.
question:
Category: U.S. RIVERS 
Clue: The Falls of Saint Anthony stop this mighty river from being navigable north of St. Paul, Minnesota
answer:
the mississippi


question:
Category: MONEY & FINANCE 
Clue: When stocks are in an upward trend, it's a bull market; as they drop, it's called this
answer:
bear market


question:
Category: BRITISH ROYAL HOUSES 
Clue: Elizabeth II
answer:

windsor