Billing occasionally charges twice during redeploys. Which TWO measures address this?

1. ✓ A Record processed MessageIds and discard repeats before applying the charge (correct answer)
2. ✓ B Enable duplicate detection on the queue for the publisher retry window (correct answer)
3. C Switch the consumer to receive-and-delete mode
4. D Reduce LockDuration to 10 seconds
5. E Disable dead-lettering

Shortcut: Service Bus is at-least-once, so a redeploy that interrupts processing after the charge but before settlement causes redelivery. Consumer-side idempotency on MessageId makes reprocessing harmless, and broker duplicate detection removes repeats caused by publisher retries. Receive-and-delete would lose messages instead.