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: ANIMALS 
Clue: There are only 3 of these animals in U.S. zoos: a 28-year-old in D.C.'s National Zoo & 2 younger ones in San Diego

Answer: pandas


Question: Category: CASTLES 
Clue: The name of this large home located in Aberdeenshire means "the majestic dwelling" in Gaelic

Answer: balmoral castle


Question: Category: ENGLISH SPELLING 
Clue: There are at least 50 common exceptions to the rule expressed by this popular rhyming mnemonic couplet

Answer:
i before e, except after c