Which of the following grape varieties is least likely to be used for rosé production in Anjou-Samur?

Tempranillo is least likely to be used for rosé production in Anjou-Saumur primarily because it is not a traditional variety of the region. Anjou-Saumur, located in the Loire Valley of France, is known for its specific grape varieties that thrive in its terroir.

Grolleau, Cabernet Franc, and Gamay are all varieties grown in this area and are commonly used to make rosé wines. Grolleau is particularly significant in this context, as it is a local variety often associated with light, fruity rosés. Cabernet Franc, while primarily known as a red wine grape, also produces vibrant rosé wines that capture the region's style. Gamay, renowned for its role in Beaujolais, can also be found in the Loire Valley and is capable of creating appealing rosé wines with juicy fruit characteristics.

On the other hand, Tempranillo is predominantly associated with regions in Spain, such as Rioja and Ribera del Duero, and though it can be made into rosé, it is not typical for the Anjou-Saumur region, making it the least likely of the options provided to be found in rosé production there.