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.

[Q]: Category: HEIR CONDITIONING 
Clue: 37-year-old Reza Pahlevi is the exiled heir to this country's "Peacock Throne"
[A]: iran


[Q]: Category: JEWELRY 
Clue: An engraved gem with a design that projects from the surface, it can be carved from onyx, agate or sardonyx
[A]: a cameo


[Q]: Category: FUN WITH THE DEWEY DECIMAL SYSTEM 
Clue: Covering the 800s, it's the only main Dewey classification that's also a Nobel Prize category
[A]:
literature