Answer: b. feeling
Explanation: David Hume made many important contributions to moral philosophy and his ethical theory continues to be relevant in areas concerning metaethics, moral evaluation, moral psychology, virtue ethics and so on. Hume argues that vice and virtue are objects of feeling. In a broader sense, although they (vices and virtue) are based upon an “internal sense or feeling,” reason is needed to ascertain the facts required to form an accurate view of the individual being evaluated (morally).