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: "W"HODUNNIT? 
Clue: He was the first U.S. president to be unanimously elected
george washington

Category: 21st CENTURY WORLD LEADERS 
Clue: "Big Love" meets "The West Wing"?  Pres. Jacob Zuma, who presides over this country from Pretoria, has 3 wives
south africa

Category: "MET"s 
Clue: All passengers on U.S. airline flights are required to pass through one of these machines

metal detector