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: FILTHY RICH 
Clue: Worth over $15 billion, Robson, son of Sam, runs this company, the USA's largest private employer
wal-mart

Category: LANGUAGES 
Clue: Mazarec is the language of the Mazarec people of Oaxaca in this country
mexico

Category: THE CANARY 
Clue: Better-known nickname of Wild West woman Martha Jane Canary

calamity jane