Given a factoid/trivia type question, generate the topic of the question. The topic is the entity the question talks about.
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Question: Aragon and Castile joined to form which country?

Answer: aragon


Question: With eight goals which Barcelona player was the leading scorer in the 2009-10 Champions League?

Answer: barcelona


Question: On which date is All Saints day celebrated in the Western Church?

Answer:
all saints' day