Which of the following is a subregion of the Aconcagua Region?

The Aconcagua Region, located in Chile, is known for its diverse geography and climate that contribute to the production of high-quality wines. Within this region, the Casablanca Valley is a notable subregion recognized for its cool climate that is particularly favorable for the cultivation of white grape varieties, such as Chardonnay and Sauvignon Blanc, as well as Pinot Noir.

Casablanca benefits from the influence of the Pacific Ocean, which moderates temperatures and creates ideal ripening conditions. This has helped to establish its reputation for producing wines that exhibit fresh fruit flavors and a crisp acidity, appealing to both local and international markets.

The other regions listed in the options do not belong to the Aconcagua Region. San Antonio is its own wine region that lies to the south of Aconcagua. Cachapoal is part of the larger Rapel Valley and Itata is located to the south in Chile, all of which are separate from the Aconcagua Region. Therefore, Casablanca stands out as the correct answer, representing a key subregion renowned for its viticultural contributions within Aconcagua.