Which flavor at Dunkin Donuts is most commonly associated with a rich, sweet vanilla taste?

The flavor that is most commonly associated with a rich, sweet vanilla taste at Dunkin Donuts is French Vanilla. This flavor is known for its creamy and smooth characteristics, which closely resemble the traditional taste of vanilla. French Vanilla is often used in a variety of Dunkin Donuts beverages, from coffee to frozen drinks, enhancing them with that distinctive sweet vanilla richness.

In contrast, the other flavors listed do not embody the vanilla profile. Peach offers a fruity and refreshing sweetness that is very different from vanilla, while Hazelnut brings a nutty and slightly sweet flavor that does not focus on vanilla notes. Raspberry provides a tart and fruity flavor, lacking any association with vanilla sweetness. Therefore, French Vanilla stands out as the flavor that best matches the description of having a rich and sweet vanilla taste.