Final answer:
Gandhi uses ethos in his letter to the Viceroy by expressing his "abiding faith in British justice," which serves to establish his credibility and appeal to shared moral values. The option (C) is correct.
Step-by-step explanation:
One example of Gandhi using ethos in his letter to the Viceroy, Lord Irwin, is "I must not withhold from your knowledge the fact that I have an abiding faith in British justice." This statement is an example of ethos since Gandhi is appealing to the credibility and moral character that he recognizes in the British sense of justice. In doing so, he is establishing his own principled stance and respect for the perceived fairness of the British, despite being in opposition to their colonial rule.
By invoking this respect, Gandhi positions himself as a reasonable man who has faith in the dialogue's potential for rectitude, which can serve to increase his credibility in the eyes of the British administration and the wider audience of the letter. This is a strategic move to develop a rapport with the Viceroy by aligning himself with shared values, and it is representative of Gandhi's genuine belief in nonviolence and justice. Therefore, option (C) is correct.