instruction:
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.
question:
Category: LITERARY OPERAS 
Clue: Operas based on this author's works include "Il Talismano", "Il Templario" & "La Prigione d'Edimburgo"
answer:
sir walter scott


question:
Category: INVENTIONS 
Clue: The delivery system for Ban deodorant, introduced in 1955, was based on this invention, patented in 1938
answer:
ball point pen


question:
Category: SPORTS BOOKS 
Clue: In 1998 the author of this controversial 1970 book was finally invited to play in a Yankees old-timers' game
answer:

\"ball four\"