An athletic shoe company is preparing to launch a new campaign for the holidays featuring existing products and their newly designed running shoe. They'd like to create an immersive 3D format that uses existing 3D shoe models to better engage the consumer. What Display & Video 360 ad format should they use?

Swirl is the correct answer because it's a Display & Video 360 ad format specifically designed for immersive 3D experiences on the mobile web. It allows users to interact with 3D models of products, rotating and zooming to view them from all angles, which perfectly suits the athletic shoe company's goal of showcasing their new running shoe in an engaging, interactive way using existing 3D assets. Native ads are designed to match the look and feel of the surrounding content, but don't inherently offer 3D interactivity. Parallax and Flipbook are not standard Display & Video 360 ad formats for 3D product interaction; Parallax refers to a scrolling effect, and Flipbook is an animation technique.