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

Ex Input:
The rivers Axe, Brue, Cary, Parrett, eta, are in which English county?

Ex Output:
castle cary


Ex Input:
Chep Lap Kok airport is located where?

Ex Output:
hong kong international airport


Ex Input:
Which Mountain Pass provides a route between Kentucky and Tennessee via the Appalachians?

Ex Output:

appalachian mountains