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.
One example: Category: WHO'S BUYING? 
Clue: YouTube, in 2006
Solution is here: google
Explanation: Google acquired, i.e. bought, YouTube in 2006 for $1.65 billion.

Now, solve this: Category: 12-LETTER WORDS 
Clue: Brittannica or World Book, for example
Solution:
encyclopedia