Which of the following is an example of a red wine?

Port is an example of a red wine because it is a fortified wine that originates from the Douro Valley in Portugal, primarily made from red grape varieties such as Touriga Nacional, Touriga Franca, and Tinta Roriz. The winemaking process typically involves fermenting the red grapes and then adding a distilled spirit to stop the fermentation, retaining natural sweetness and increasing alcohol content. This results in a rich and often sweet wine, characterized by flavors of dark fruits, chocolate, and spices.

In contrast, Cava and Prosecco are both sparkling wines made from white grape varieties. Cava is primarily produced in Spain, mainly from the Macabeo, Parellada, and Xarel·lo grapes, while Prosecco is made in Italy predominantly from the Glera grape. Chardonnay is a white grape variety used in many types of wine, including still, sparkling, and sometimes even in the production of sweet wines, but it does not produce red wine. Therefore, the only correct choice in this case, which accurately represents a red wine, is Port.