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: INVESTING WITH WARREN BUFFETT 
Clue: Buffett calls the purchase of this insurance company one of his best investments; he first bought its stock in 1951
geico

Category: NOTORIOUS 
Clue: He established a commune for his "family" on the Spahn Ranch outside Los Angeles
manson

Category: THE CIVIL WAR 
Clue: McClellan, Burnside, Hooker & Meade successively headed this army

the army of the potomac