Answer:
B. framed narrative
Step-by-step explanation:
A framed narrative is an introductory story that makes way for the big story or some other stories to follow. Mary Shelley's Frankenstein contains a framed narrative because it begins with the letters Walton wrote to his sister, before it progresses to the main story which is that of Victor and his experiments in the laboratory that resulted in the creation of the monster.
Just as a frame contains a picture, so does the framed narrative contain the big story.