Why is studying an author's culture important?
a. to the reader understand the use of figurative and connotative language in the story
b. to the reader understand how the characters are able to overcome the story's conflict
c. to the reader understand the quality of the writing and the author's level of education
d. to the reader understand the underlying values and beliefs of the characters

(the answer is d)

The answer is D.

Culture refers to a particular ‘way of life’ (experience), involving religion, race and nationality, as well as things like food, dress code and manners. Literature has been defined as "the human experience."  It is the outpourings of the artist's heart and soul.  To know about the personal background of this artist, therefore, only makes sense. For example Ernest Hemingway in "A Farewell to Arms" , his experience are in the background of this novel.

the switch in narration increases the proximity of the narrator to the main character and the reader can perceive information only through the filter of a single character.