Answer:
D. with the speaker's conversations with the raven
Explanation:
When you read “The Raven” from Edgar Allan Poe you get the feeling of unrest and uncertainty, with the constant pounding and no explanation of what is making the sound. After the narrator finds out that is a raven he engages in a conversation with the creature, this could only drive the scene to something unreal and presumably mad, this way Poe creates a unity of effect of madness.