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 consistency, answers should be in all lower cased letters.

Category: BIG CITY LIFE 
Clue: The beginning of this regulation of land & building use dates from a 1916 New York City ordinance
zoning

Category: MONTREAL EXPOSE 
Clue: The Basilique Notre-Dame has one of the largest ones of these in North America; it weighs 12 tons
bell

Category: "OW"! 
Clue: Not a consonant

a vowel