- As a backup for a VAST asset
- When a video ad contains interactive features
- For videos served on mobile devices
- When VAST is not supported
The correct answer is: When VAST is not supported
Explanation: VPAID is a rich media creative that is delivered as an additional media asset type within a VAST tag. VPAID is typically used for ad interactivity in a publisher’s in-stream video player. VPAID Asset would be used when the VAST is not supported.