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: MUSICAL GROUPS 
Clue: This outspoken rap group led by Chuck D. took its name from a song title that ended "Number One"
public enemy

Category: THE INSTRUMENT OF DEATH 
Clue: In 1793 Jean-Paul Marat was retired in the bath with one of these
a knife

Category: THE UNITED NATIONS 
Clue: (Sofia of the Clue Crew outside the U.N. building)  The land the U.N. complex is built on was donated by this wealthy businessman

john d. rockefeller