In which flavor can one find a rich combination of chocolate and creamy flavors at Dunkin Donuts?

The flavor that features a rich combination of chocolate and creamy flavors at Dunkin Donuts is the Frozen Hot Coco. This drink is specifically designed to provide a decadent chocolate experience, blending hot cocoa flavors with a creamy texture, often served frozen for a unique, enjoyable treat. The emphasis on a rich chocolatey taste combined with creaminess makes this option stand out.

Other options such as hazelnut, caramel, and French vanilla, while they may offer distinct flavors, do not embody the combination of chocolate and cream in the same way. Hazelnut has a nutty profile, caramel lends a sweet buttery taste, and French vanilla offers a smooth and rich vanilla flavor. None of these options deliver the chocolate-centric experience that Frozen Hot Coco provides, which is why it is the correct answer.