Answer:
A. The rules of reality that govern the story
Step-by-step explanation:
The setting of a story etablishes how the world and how the rules of the wolrd that exists within the story is going to be ruled, this creates for a reality in which the reader immerses and starts to imagine the events that are unfolding in the story. According to Watching the World from the Riverban, the setting of the story creates the rules of reality that govern the story, for example in the lord of the rings, if Tolkien hadn´t had taken the momento to explain to you his world, everything would feel unrealistic and over the top, but because you understand the rules and the context when reading it, it makes perfect sense.