In the Midwest region of the United States, which is often characterized by its fertile soil and favorable climate for farming, the primary type of agriculture practiced is cattle ranching and crop farming. However, among the options you've provided, cattle ranching would be the most applicable choice for the dark-shaded areas on the map, as these regions are known for livestock production, particularly beef.
If you have another type of agriculture in mind or specific details from the map could help clarify further, please feel free to provide additional context!