The correct answer is D. He is coping with the loss of Lenore, whom he loved, and the Raven's presence is slowly driving him mad. He pictures the Raven as an evil presence and power. He tries to find out what does that creature want but the bird just keeps repeating "Nevermore". The continuous repetition of this word drives him to insanity. He keeps asking the Raven questions that he already knows the answer but just wishes to hear them from someone else. Although he tries to communicate with the raven, the bird just keeps replying the same, "Nevermore". This situation makes him really madly crazy.