Answer: A.) It connects the author’s imagined scenario to his claim about the Athenians.
Explanation: To understand the rhetorical function of this sentence, it is important to consider how the author’s imaginary scenario fits into his broader line of reasoning. In the fourth paragraph, the author brings up “the Greeks,” anticipating that his audience will mention them to refute his claim that “there never has been an artistic age, or an artistic people.” This implies that his audience believes that ancient Athens was more hospitable to artists than their own nineteenth-century society is. Then, in the eighth and ninth paragraphs, the author responds to this anticipated objection by describing the hypothetical persecution of a contemporary English artist. By revealing that the imagined events really happened to Phidias in supposedly “artistic” Athens, the final sentence shows that the imaginary scenario supports the author’s earlier claim that the Athenians were not an artistic people (“Were they . . . do neither”). The author’s conclusion thus brings his argument to a unified end, simultaneously wrapping up his discussion of the Athenians and refuting the main objection to his overarching claim about how artists fit into their societies.