The choice of narrator affects the plot of a narrative in the following way:
d) The narrator's point of view affects the amount of information the reader receive.
Whenever the narrator is a character in the story, he may interact with other characters or may witsness certain events. These interactions are received by the reader through the narrator's eyes, so it affects the view of the reader. Moreover, the reader cannot know anything the narrator does not know, because it is his link to the story, and that limits the information the reader may receive.