The best for me is D
First ,because the narrator lost Lenore; he is hurt by this loss and when he hears the knock on the door he imagines it is her or her presence. Second , The Raven is in some way telling him or reminding him that Death comes to us all. The bird is a sign we all depart to never return.. and it is this message that drives him mad .Last but not least, the Raven only mutters NEVERMORE, a word which has a negative sense; it means Lenore will never ever be alive again and that he will never be happy again.Never is a word which will haunt him for the rest of his life.
The answer would be thesis statement