Which of the following is not one of the top three white grape varieties of Chile?

Zinfandel is not recognized as one of the top three white grape varieties in Chile. The country is primarily known for its production of white wines from Sauvignon Blanc, Chardonnay, and to a lesser extent, Muscat of Alexandria.

Sauvignon Blanc has gained a strong reputation for its vibrant acidity and expressive fruit characteristics, particularly in regions such as Casablanca and Leyda. Chardonnay, on the other hand, is also significant in Chile, with a range of styles produced, from crisp and fruity to rich and buttery. Muscat of Alexandria shows a slight presence in some regions but does not dominate the white wine landscape compared to the other two.

Zinfandel is predominantly associated with California and is primarily grown for red wine production. It is not commonly cultivated as a white variety in Chile, which further establishes its position as not being among the country's top white grape varieties.