Which excerpts shows the clearest example of ethos from the of a canyon

D. I have had the unique opportunity to observe first-hand some of the differences between the environment of a free river and a power-plant reservoir.

Explanation:

In this question, the clearest example of ethos occurs in option D. This relates to the text "The Dam-nation of a Canyon." Ethos refers to an appeal to authority. This occurs when an author tries to persuade the audience of an opinion by appealing to his own credentials. In this example, this is what occurs in option D, as the author tells us that he has had the opportunity to observe first-hand some of the differences between the environment of a free river and a power-plant reservoir.

Explanation: