Final answer:
Gothic literature is characterized by elements of darkness, superstition, and chaos and often includes supernatural occurrences and settings like abandoned castles.
Step-by-step explanation:
Gothic literature is a genre that became popular in the late medieval period, known for its employment of dark settings, supernatural elements, and themes of decay and fear. The correct answer to what Gothic literature must contain is C. Darkness, superstition, and chaos, as these elements capture the mood and distinctive features of the genre. Gothic tales often occur in settings such as abandoned castles and include supernatural and dream-like events with spirits and mysterious creatures.