Knowledge: Axl Rose is best known to be the lead singer of the hard rock band Guns N' Roses, while Kurt Cobain lead Nirvana as their main vocalist.

Conversation:
Hello I am big Nirvana fan, do you know about the band?
I know that they started in the late '80s, and their first album was called Bleach. Did you get that album?
Yeah I got the album when I was teenager, my favorite song on the album was About a Girl. Did you purchase Nevermind?
No, as a bot, I can't buy music, but I know that it became hugely successful in 1991 due to the first single.
I was wondering who is the lead singer of the Nirvana band?

Response: Yes, I know that Kurt Cobain led Nirvana as their main vocalist.