Which grape variety is primarily used for producing Chardonnay wines?

Chardonnay is the grape variety primarily used for producing Chardonnay wines, making it the correct choice. This versatile white grape is known for its ability to adapt to various climates and soil types, resulting in a wide range of styles from crisp and fruity to rich and oaky. Chardonnay is one of the most widely planted white grape varieties in the world and serves as the primary varietal in many famous wine regions, including Burgundy in France and parts of California and Australia.

The other grape varieties listed—Pinot Noir, Riesling, and Sauvignon Blanc—are distinct and are used to make different styles of wines. Pinot Noir, while often blended with Chardonnay in sparkling wines like Champagne, is a red grape variety. Riesling is celebrated for its aromatic profile and high acidity, common in aromatic white wines, but is not primarily used to make Chardonnay. Sauvignon Blanc is another well-known white grape that produces wines with bright acidity and herbaceous notes, yet it is separate from the Chardonnay grape and does not contribute to producing Chardonnay wines.