A Container App processes Service Bus messages and must cost nothing while the queue is empty. Which configuration achieves scale-to-zero?

1. A An HTTP scale rule with minReplicas 1
2. ✓ B A KEDA Service Bus queue scale rule with minReplicas 0 (correct answer)
3. C A CPU scale rule with minReplicas 0
4. D Manual scaling set to 0

Shortcut: Only event-driven KEDA scalers can wake an app from zero. CPU and memory rules require a running replica to report metrics, so they cannot scale from zero.