What is the backup to the online platform for drill validation?

The backup to the online platform for drill validation being the sign-off book is appropriate due to its role in maintaining a tangible record of completed drills. This book serves as an official log where each drill and participant's involvement can be documented by personnel, ensuring there is a reliable method of verification even if the online system is unavailable.

In scenarios where the digital format may fail or be intermittently accessible, the sign-off book provides a consistent and essential backup. It allows personnel to continue documenting critical training activities without interruption. Furthermore, having a physical record can be particularly useful during audits or reviews to confirm that the necessary training protocols have been followed and that personnel are adequately prepared.

The other options, while they may represent methods of collecting feedback or logging training activities, do not serve the same purpose as the sign-off book in terms of providing a comprehensive, verifiable backup for drill validation records. Feedback forms and training logs can be more subjective in nature and may lack the formal structure that an official sign-off book provides. Physical paperwork may also not directly correlate to drill validation specifically. Thus, the sign-off book is integral for ensuring accountability and traceability in drill performance verification.