Which of the following is a key white grape variety in Dao DOC?

Encruzado is a key white grape variety in the Dão DOC region of Portugal, known for producing high-quality white wines. It thrives in the region's climate and soil conditions, contributing to the distinctive character of Dão wines. Encruzado is appreciated for its ability to create wines that are aromatic, with a balanced acidity and complexity, often featuring notes of citrus, peach, and floral hints.

The other varieties mentioned, while significant, are more often associated with red wines in Portugal. Touriga Nacional, for instance, is a prominent red grape variety known for its role in fortified wines and blends, especially in the Douro Valley. Tinta Roriz, also known as Tempranillo, is another red variety that is widely planted and used primarily for red wine production. Alfrocheiro is another red grape variety commonly found in the Dão region but does not play a significant role in white wine production. Hence, Encruzado stands out as a crucial variety for white wine in the Dão DOC.