Which of the following is NOT a key grape variety of Vinho Verde DOC?

In Vinho Verde DOC, the key grape varieties are primarily focused on white wines, with Alvarinho, Trajadura, and Avesso being significant contributors to the region's renowned wine production. Alvarinho is particularly celebrated for its aromatic complexity and is often associated with high-quality Vinho Verde. Trajadura and Avesso also play essential roles in blending, helping create the unique profile of Vinho Verde wines that are fresh, zesty, and vibrant.

Tinta Roriz, on the other hand, is a red grape variety also known as Tempranillo in Spain, and while it is important in other Portuguese wine regions, notably the Douro Valley and Dão, it is not a primary grape in the production of Vinho Verde. This distinction regarding the dominant grape varieties in Vinho Verde makes it clear why Tinta Roriz is the correct answer to this question.