Final answer:
Sentence B represents the claim about the effectiveness of arguments regarding collective responsibility for reparations to African Americans for slavery and Jim Crow.
Step-by-step explanation:
The sentence that represents the claim is B: "For one, no amount of resonant argumentation about "collective responsibility" will convince the modern American populace as a whole—now composed of a great many immigrants and their children — that "they" owe black people for slavery and Jim Crow." This sentence provides a definitive statement about the effectiveness of an argument concerning reparations, suggesting that it is unlikely to persuade the broader American populace, which includes many immigrants and their descendants, of a collective responsibility to compensate African Americans for historical injustices.