Given a factoid/trivia type question, generate the topic of the question. The topic is the entity the question talks about.

[Q]: Princess Estelle, Duchess of Ostergotland, granddaughter to King Carl XVI Gustaf, became 2nd in line to what nation's throne when born in 2012?
[A]: carl xvi gustaf of sweden


[Q]: In America, as what was Bill Shoemaker famous?
[A]: bill shoemaker


[Q]: On television who live at 742 Evergreen Terrace, Springfield?
[A]:
the simpsons house