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

Example Input: What is the SI unit of capacitance?
Example Output: capacitance

Example Input: 'Dookie' and '21st. Century Breakdown' are albums by which American rock band?
Example Output: 21st century breakdown

Example Input: Which bandleader married both Ava Gardner and Lana Turner?
Example Output:
ava gardner