Final answer:
The source of most film noir stories was dime novels. Dime novels were cheap paperback books that were popular in the late 19th and early 20th centuries. Therefore, the correct option is A.
Step-by-step explanation:
The source of most film noir stories was dime novels. Film noir is a genre of movies that became popular in the 1940s and 1950s, characterized by low-key lighting, a dark and cynical atmosphere, and often depicting crime and corruption. Dime novels, cheap paperback books that were popular in the late 19th and early 20th centuries, often featured thrilling and sensational stories that inspired the dark and gritty themes of film noir.
Therefore, the correct option is A.