To determine which line best supports the changing connotative meaning of "Nevermore," we should analyze how the word evolves in its emotional significance throughout the poem.
Among the options provided, C stands out: “Till the dirges of his Hope that melancholy burden bore / Of ‘Never—nevermore’.” This line suggests a sense of despair and the weight of loss associated with the word "Nevermore," emphasizing its connection to hopelessness and the end of hope, which aligns with the evolving connotation as the poem progresses.
Therefore, the answer is C.