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: SUPERHEROES 
Clue: For a while the Hulk was gray, but now he's this color
green

Category: WE HAVE THE TECHNOLOGY 
Clue: Smile!  In 1888 this American introduced the first simple consumer camera to use roll film
eastman

Category: LANDING AT JFK 
Clue: In June 1961 JFK met with this rival world leader for 2 days in Vienna to discuss a growing crisis in Europe

khrushchev