The author's purpose is to highlight the persistence of racism.
Explanation:
The short story "Of the Coming of John" shows how even if a black citizen is well educated, educated and promotes the good of society, with progressive attitudes and actions, he will always be seen as inferior to white citizens, because when the population looks for him, she will see him only as a black man. This is because racism is so ingrained in our society that it prevails, regardless of the situation.
When the author quotes this short story, he wants to emphasize this theme and provoke people's reflection on the racist concepts they encourage.
I am pretty sure the correct answer to this question your looking for would be: C.a static character whose beliefs and behaviors don't change over the course of the story. I hope i helped! :)