Answer :
Think about your choices and what they mean.
In Mary Shelley's Frankenstein, the dark storm flashes back to events are going to become uneasy and scary. We know that a flashback is a scene that has already happened earlier in the story, meaning that this is not the correct answer.
Anecdotes are short stories about a real incident or person, and Frankenstein is a fictional story, meaning this is also not the correct answer.
Transitions would be to change from one scene to another, which wouldn't exactly show that events are going to become uneasy and scary, which leaves us with only one option left.
The correct answer is C. foreshadows. Foreshadowing gives a hint as to what will happen next in the story, which, in this case, would be the dark storm. For further proof of this being the correct answer, I have also taken this quiz and got the answer right. Hope this helped!