The correct answer is:
It engages their sense of ethics.
Why: The word choice in this excerpt highlights the moral gravity of the slave trade, using terms like "enormous," "dreadful," and "wickedness." This language evokes a strong sense of ethical responsibility and moral outrage in readers, urging them to confront the immorality of the slave trade and prompting them to consider the ethical implications of its continuation. Wilberforce's emphasis on the overwhelming wrongness of the trade seeks to engage the audience's conscience, fostering a sense of moral duty to support abolition.