To accurately determine the conclusion from the options given, we need to consider the significance of the refrain in relation to the poem's theme. Since the specific poem is not provided, I will guide you based on general characteristics of Dunbar's work that often explore themes of love and loss.
If the refrain repeats a sentiment related to the inevitability or permanence of loss, option b. The poem reflects the power of finality when a person loses love would be a strong conclusion.
If the refrain conveys a sense of emptiness or numbness, then option a. The poem shows how losing a loved one results in a person feeling constant numbness might be most accurate.
If the repetition suggests ongoing questions about love’s absence, option c. The poem emphasizes the speaker's feeling of uncertainty and the absence of love could be the right choice.
Lastly, if the refrain conveys a shift in perception about the world (for example, seeing the sky as dreary after a loss), then option d. The poem highlights how the loss of love has caused the speaker to see the sky as always clouded could be fitting.
Without the specific text of the poem, I suggest determining which theme resonates most closely with the refrain used in the poem.