To determine which lines from the poem best support the answer to Part A, we need to identify the main theme or argument presented in Part A. If Part A addresses the idea of life or experiences being transient or illusory, then the lines that highlight these concepts would be the best fit.
The lines "All that we see or seem / Is but a dream within a dream." (Lines 10-11) express the idea that reality may not be as it seems and that our experiences are akin to dreams, which would strongly support the notion of transience or illusion.
Alternatively, the lines "You are not wrong, who deem / That my days have been a dream" (Lines 4-5) also focus on the dream-like quality of the speaker's life.
Depending on the specific focus of Part A, either of these pairs of lines could be appropriate. However, the first option about reality being a "dream within a dream" directly addresses the theme of perception and the ephemeral nature of experiences, making it particularly compelling.
In summary, if Part A focuses on transience or the dream-like state of reality, the best supporting lines would be:
"All that we see or seem / Is but a dream within a dream." (Lines 10-11)