instruction:
Given a factoid/trivia type question, generate the topic of the question. The topic is the entity the question talks about.
question:
Which actor spoke the line I love the smell of napalm in the morning* in the 1979 film Apocalypse Now?
answer:
apocalypse now

question:
Which two brothers had hits with Cathy's Clown and Wake Up Little Susie?
answer:
cathy's clown

question:
Boris Godunov ruled, first as de facto regent and then as ruler, in which country?
answer:
boris godunov