The answer is C: Persuading readers to change their attitudes.
Great works of literature throughout history all have reshaped society´s views on an endless number of attitudes, behaviors, conceptions, and ideas. Indeed, this is one possible higher purpose of literature. The examples are virtually countless, but one could mention Tolstoy´s Ana Karenina and how it impacted society´s views on seduction and love, or Dostoyevsky´s Karamazov brothers which made society revaluate views on family ties, responsibility, humaneness and even the understanding of a divine being and its role in one´s own life.