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: EUROPEAN FICTION 
Clue: This 1915 story says, "His numerous legs, which were pitifully thin... waved helplessly before his eyes"
metamorphosis

Category: BRITISH ROYALTY 
Clue: Before Prince Andrew, he was the last Duke of York
king george vi

Category: PSYCHOLOGY TERMS 
Clue: This 2-word term has its origins in a hostage-taking that followed the botched 1973 Norrmalmstorg bank robbery

stockholm syndrome