Answer:
C. The 12 years of hardship that Hrothgar and his people suffer because of Grendel.
Step-by-step explanation:
In a story, the exposition reveals the necessary background information about the characters, the setting or the events for a reader to understand what the main conflict or situation is going to be.
The exposition usually takes place at the beginning to establish the story's main intention, and can be revealed through description or dialogue.