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

Example Input: Which is the only Avril Lavigne song to have reached No.1 in the US Billboard Chart?
Example Output: avril lavigne

Example Input: What actress, born in Muscat, Oman, began acting on Australian television on Paradise Beach and Home and Away and is known for her roles in Wedding Crashers (2005), Hot Rod (2007), Definitely, Maybe (2008) and Confessions of a Shopaholic (2009)?
Example Output: definitely, maybe

Example Input: What prestigious learning institution is in Cambridge, Massachusetts, US?
Example Output:
cambridge, massachusetts