Answer:
A). An appeal to ethics.
Step-by-step explanation:
Ethos meaning 'appeal to ethics' is demonstrated as one of the three 'modes of persuasion' offered by the famous Greek philosopher Aristotle. These three modes(ethos, logos, and pathos) aid to persuade the readers to believe in the ideas or thoughts conveyed by the author. Ethos(appeal to ethics) convinces the audience by foregrounding the credibility of the author by invoking authority in the argument which aids to persuade the audience ethically.
In the given question, the reference to ethics('It is only fair....') aids to persuade the readers by appealing to them ethically by establishing the credibility of the author. Thus, option A is the answer as the statement exemplifies 'ethos'.