How does the story's point of view most clearly strengthen the story?

a. when the narrator directly addresses the reader with various questions a personal connection is created.
b. when the narrator reveals his personal thoughts and feelings, it allows the reader to better understand the conflict going on within him.
c. when the narrator switches from one character to the next, the reader can form an unbiased opinion about the different versions of the story.
d. when the narrator tells the story without any personal bias, the reader gets an objective view of the situation