Answer: B. Frankenstein's visits to the tombs.
Explanation: Gothic fiction is a style of writing that is characterized by elements of fear, horror, death, suspense and gloom, as well as romantic elements, such as nature, individuality, and very high emotion. From the given options, the one that represents an element that most closely belongs to Gothic literature is the corresponding to option B: Frankenstein's visits to the tombs, because tombs are usually present in Gothic settings.