Which is not one of the top three red grape varieties grown in southern France?

The top three red grape varieties grown in southern France include Grenache, Syrah, and Carignan, which are all well-suited to the region's climate and soil conditions. Grenache is particularly prominent, often forming the backbone of many blends in the area, while Syrah is valued for its depth and complexity. Carignan, although less prominent than Grenache and Syrah in terms of stature, still plays a significant role in southern French viticulture, especially in blends.

Chardonnay, on the other hand, is primarily a white grape variety and is not included in the top red grape varieties of this region. Its cultivation is more common in regions known for white wine production, such as Burgundy and Champagne. Thus, highlighting the distinctions between red and white grape varieties helps clarify the answer, asserting that Chardonnay is not related to the top three red grape varieties of southern France.