The best example of a gothic story line is a teenager believing his new neighbors have placed an ancient curse on him (D).
Gothic fiction is a genre that combines fiction and horror. It often contains death and sometimes romance. Even though, option C is about a dying woman, the storyline does not fill the reader with terror, nor is it fictional. However, an ancient curse is fictional and might cause the reader to be terrified.
The effect of the authors' use of foreshadowing in Secret In Slovakia is that he wanted to portray the altogether different character of Aunt Gertrude from what the author's family had perceived her to be.