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: PICTURE BOOK TITLE ANIMALS 
Clue: "If You Give a ____ a Cookie"
mouse

Category: INDIANA 
Clue: Indiana's state motto is "The Crossroads of" this
america

Category: WORLD HISTORY 
Clue: In 1923 France & Belgium occupied this German industrial region named for a Rhine tributary

the ruhr