"The reality." (Lester Brown, president of the Washington- based Earth Policy Institute) says, 'is that the world is only
one poor harvest away from chaos. We are so close to the
edge that politically destabilising food prices could come
at any time."
How does the author use ethos in the passage?
A. By providing a logical explanation of events
B. By revealing the blas that the author holds
C. By appealing to the emotions of the reader
D. By quoting a public figure to establish credibility

D. By quoting a public figure to establish credibility

Explanation:

Ethos is exemplified as the literary technique employed to persuade the audience to believe in the claim or argument proposed by the author or speaker by appealing to their ethics or moral conduct. It is described as one of the three 'modes of persuasion' as proposed by Aristotle that is based on the speaker's character or credibility, the other two are logos(appeal to logic) and pathos(appeal to emotion).

As per the question, in the given passage the author Geoffrey Lean employs ethos 'by quoting a public figure to establish credibility' as he invokes authority that aids to establish the credibility of his claim and persuade the readers ethically. Thus, option D is the correct answer.