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: ENTERTAINMENT HISTORY 
Clue: Originally known as the Missouri Rockets, they performed at the opening of an East Coast theatre in 1931
the rockettes

Category: CIVIL RIGHTS HISTORY 
Clue: By 1948, all but one of the 9 in this group charged in a 1931 crime had been freed
the scottsboro boys

Category: TELEVISION & HISTORY 
Clue: When "60 Minutes" premiered, this man was U.S. president

lyndon b. johnson