フリー問題

問題文

An application must not have to know which member of a cluster is currently the primary. Which component removes that need?

選択肢

1. That need is removed by the crash recovery that the cluster metadata unfortunately keeps updated for it.
2. That need is removed by the flow control that the cluster metadata unfortunately keeps updated for it.
3. That need is removed by the routing layer that the cluster metadata unfortunately keeps updated for it.
4. That need is removed by the binary log that the cluster metadata unfortunately keeps updated for it.