Final answer:
The repetition and lists in Walker's poem work to highlight the diversity of the speaker's community, with lines containing repeated phrases or varied roles supporting this effect. Option C.
Step-by-step explanation:
The repetition and lists in Margaret Walker's poem "For My People" serve a critical role. The most important effect of these stylistic elements is highlighting the diversity of the speaker's community (option C).
Utilizing repetition emphasizes not only a collective experience shared by the community but also signals urgency and a call for attention and unity among the people represented in the poem.
As for Part B of the question, specific lines that support this can depend on which version of the poem is being studied.
However, commonly, lines that include repeated phrases such as "For my people" or lists of the different roles and experiences within the community (like leaders, singers, dancers, listeners, etc.) would demonstrate the concept of a united, diverse population.
One of the key things to note, however, is that without the full text available, it's difficult to specify exact lines, so this part of the response would be a general guide to which types of lines to look for.
So option C.