TASK DEFINITION: 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.
PROBLEM: Category: WORLD LEADERS 
Clue: Early in the 20th century, he took one of many pseudonyms, Nguyen Ai Quoc, or "Nguyen the Patriot"

SOLUTION: ho chi minh

PROBLEM: Category: HISTORIC NAMES 
Clue: 2 of the people who witnessed his execution were John Wilkes Booth & Stonewall Jackson

SOLUTION: john brown

PROBLEM: Category: SCIENTIFIC DISCOVERIES 
Clue: They got their name because the man who discovered them in 1895 had no idea what they were

SOLUTION:
x-rays