Final answer:
Edgar Allan Poe uses the repeated symbol of a dying fire as a poignant emblem of fading hope and yearning for the lost Lenore, key in creating a unity of effect of longing in "The Raven".
Step-by-step explanation:
Edgar Allan Poe creates a unity of effect of longing in "The Raven" through option a. with the repeated symbol of a dying fire. This imagery, as seen in lines like "And each separate dying ember wrought its ghost upon the floor," eloquently parallels the narrator's fading hope and the intense longing for his lost love, Lenore. The dying fires symbolize both the literal end of the day and the metaphorical extinguishing of life and happiness, thereby underscoring the theme of longing throughout the poem.
Further explaining this creative choice, the dwindling fire represents the dwindling of the narrator's spirit as he confronts his sorrow. The repetition of this symbol throughout the poem enhances the oppressive atmosphere of despair and unfulfilled desire, creating a hypnotic melancholy that captures the reader's imagination. Alongside the repeated reference to the lost Lenore and the ominous presence of the raven, the dying fire is a potent emblem of the unattainable past and the ceaseless yearning that defines the poem's mood.