The answer is D: The dead are constantly remembered by those who mourn.
In this poem by Edgar Alan Poe, he is lamenting the passing of a loved one. The narrator makes the reader acquainted with his sorrow at having been so fortunate as to have loved, but so unfortunate to have lost this love to death. In the last stanza, he makes his days and his dreams all revolve around the figure of an eternal, but ethereal, one who has passed away and seems to haunt his every thought.