"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 logos in the passage?
a. by appealing to the emotions of the reader
b. by quoting a public figure to establish credibility
c. by revealing the bias that the author holds
d. by providing a logical explanation of events