フリー問題

問題文

Snapshots are taken frequently and a copy is also sent to the far site. Which option correctly identifies the later needs that the pair covers but neither covers alone?

選択肢

1. The pair covers a quick undo and a lost disk that one of them alone would leave open in the configuration.
2. The pair covers a quick rollback and a lost room that one of them alone would leave open in the configuration.
3. The pair covers a quick undo and a lost stream that one of them alone would leave open in the configuration.
4. The pair covers a quick undo and a lost shelf that one of them alone would leave open in the configuration.