Which sub-region of Napa Valley is known for producing full-bodied Cabernet Sauvignon with ripe-black fruit flavors?

Oakville is recognized as a premier sub-region within Napa Valley particularly for its production of full-bodied Cabernet Sauvignon that showcases ripe black fruit flavors. The region benefits from a unique combination of climate, soil, and geography that is ideal for growing high-quality Cabernet Sauvignon grapes. The warm days, cool nights, and diverse soil profiles contribute to the development of complex, concentrated flavors in the grapes, which translate into wines characterized by rich fruit notes, robust structure, and age-worthiness.

In contrast, Sonoma is a larger, diverse wine region that encompasses various microclimates and grape varieties, but it is not as exclusively linked to the reputation of full-bodied Cabernet Sauvignon as Oakville. Santa Barbara, while known for a range of varieties, is more recognized for its cooler climate wines, particularly Pinot Noir and Chardonnay, rather than the bold Cabernet Sauvignon style. Pasco does not refer to a sub-region within Napa Valley or a recognized wine region in the context of Napa Valley Cabernet Sauvignon production.

Overall, Oakville stands out for its focus on crafting high-quality Cabernet Sauvignon, making it the correct choice for the description given.