Based on the context provided, it seems that you are referring to a map that indicates different regions, but without the visual representation, I cannot determine the correct answer. However, I can provide some historical context about cotton cultivation during the 1860s.
In the 1860s, the primary region for cotton cultivation was the Southern United States, which would correspond to a label usually indicating the Southern region. If one of the regions labeled A, B, C, or D refers to that area, then that would be the correct choice.
Please refer to the regions marked on your map and identify which one corresponds to the Southern U.S. for cotton production in that era. If you can provide more details about each labeled region, I'd be happy to help you further!