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: In which city could you visit the Anne Frank House?

Answer: anne frank house


Question: Who married the woman who was to become Queen Beatrix of the Netherlands, on 10 March 1966?

Answer: beatrix


Question: What are Lithium, Sodium, Potassium, Rubidium and Caesium?

Answer:
lithium