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 simplicity, answers should be in all lower cased letters.

Category: MATHLETES 
Clue: John Nash has a beautiful mind that contributed to this "theory" of strategic decision making
game theory

Category: THE NATIONAL MUSEUM OF HEALTH & MEDICINE 
Clue: Among lesser-known body parts at the museum, see the leg Gen. Daniel Sickles lost at this July 1863 battle
gettysburg

Category: "E"ASY DOES IT 
Clue: Born in Norway, he patented the first practical outboard motor for boats

evinrude