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: SALAD DRESSING 
Clue: This national-named dressing often made with ketchup is found in deli sandwiches
russian dressing

Category: THE HISTORY OF APRIL 9th 
Clue: 1959: NASA publicly introduces Messrs. Glenn, Shepard & the rest of this program's 7 astronauts
mercury

Category: EDDIE MURPHY MOVIES 
Clue: Art Buchwald was awarded original story credit for this film in which Eddie played an African prince

coming to america