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: WHAT SIGN ARE YOU? 
Clue: You're a 7' tall red octagon with white letters; you tell folks to do this, & dang it, you mean it
a stop sign

Category: 10-LETTER NAMES 
Clue: Roman myths called Hades' wife Proserpina, while the Greeks knew her by this name
persephone

Category: 19th CENTURY FRANCE 
Clue: This son of the King of Holland followed uncle Napoleon's example & became Emperor of the French in 1852

napoleon iii