Answer: c. to establish his credibility as someone who has disobeyed laws he doesn't agree with.
Ethos is a rhetorical device in which the author makes an appeal to morality. The author tries to establish his credibility through the use of moral examples in order to convince his audience. Henry David Thoreau makes an appeal to ethos in his text by describing how he lived by his own ideals. Thoreau preached civil disobedience, specifically in the form of tax avoidance. He makes an ethical claim by living in this way and personally refusing to pay his taxes.
