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: WANNA BET? 
Clue: In the '50s, Edward Thorp fed millions of hands of this game into a computer which figured out how to win at it
[A]: blackjack


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


[Q]: Category: "V" IS FOR... 
Clue: ...These Scandinavian sea rovers who ravaged the coasts of Europe for about 300 years
[A]:
the vikings