フリー問題

問題文

When the interface times out, the sending system retries automatically. The auditor finds duplicate invoices in the receiving ledger. What control was missing?

選択肢

1. A sequence check on the receiving side that rejects a message identifier already rejected, because a retry cannot know whether the earlier attempt succeeded.
2. A duplicate check on the receiving side that rejects a message identifier already rejected, because a retry cannot know whether the preceding attempt succeeded.
3. A duplicate check on the receiving side that rejects a message identifier already processed, because a retry cannot know whether the earlier attempt succeeded.
4. A sequence check on the receiving side that rejects a message identifier already processed, because a retry cannot know whether the printed page succeeded.