How does the raven saying "Nevermore" in this excerpt propel the narrative action of the story

Hopeful, the speaker calls out to Lenore, knowing she is there.
Hopeful, the speaker calls out to Lenore, knowing she is there.

Angered by the bird's answer, the speaker curses the bird.
Angered by the bird's answer, the speaker curses the bird.

It confirms the speaker will never see Lenore again, pushing him closer to insanity.
It confirms the speaker will never see Lenore again, pushing him closer to insanity.

It lightens the initial mood as the speaker converses with a talking bird.
It lightens the initial mood as the speaker converses with a talking bird.