Final answer:
The Nancy Drew Mystery Stories belong to the mystery genre, where young detective Nancy Drew solves various crimes and mysteries using her wit and bravery. The correct option is 1.
Step-by-step explanation:
The Nancy Drew Mystery Stories, which first appeared in 1930, are centered around the genre of mystery.
The subject matter of these stories involves elements such as crime-solving, suspense, and the pursuit of understanding the unknown or uncovering secrets. Nancy Drew herself is a young amateur detective who uses her intelligence, courage, and resourcefulness to solve various mysteries.
This series falls squarely into the mystery genre rather than horror, romance, or science fiction, and it has been beloved by generations for its thrilling narratives and engaging protagonist.