instruction:
Given a factoid/trivia type question, generate the topic of the question. The topic is the entity the question talks about.
question:
Princess Estelle, Duchess of Ostergotland, granddaughter to King Carl XVI Gustaf, became 2nd in line to what nation's throne when born in 2012?
answer:
carl xvi gustaf of sweden


question:
The 1987 film 'Roxanne' was adapted by actor Steve Martin from which Edmond Rostand play?
answer:
roxanne


question:
Who played Cat Ballou in the 1965 film of the same name?
answer:

cat ballou