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.
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Question: Category: ENDS IN "FF" 
Clue: The heaviest of dog breeds, it can exceed 180 pounds

Answer: mastiff


Question: Category: '60s ROCK 
Clue: In July 1967 this group's "Light My Fire" became Elektra Records' first No. 1 single

Answer: the doors


Question: Category: CHRISTIANITY 
Clue: It can refer to the birth of Christ, his second coming or the 4 Sundays before Christmas

Answer:
advent