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: THE WIZARDS 
Clue: Novelist who wrote the line "I'm really a very good man; but I'm a very bad wizard"
l. frank baum

Category: WALK INTO A "BAR" 
Clue: A pier, wharf or landing place: San Francisco has a famous one
embarcadero

Category: BRITISH NOBILITY 
Clue: In 1702 military hero John Churchill became this "man" as the first Duke of it

marlborough