In a robust Distributed Lock recipe, why does each client only watch the Znode with the sequence number *immediately preceding* its own?

1. A To mitigate the 'Herd Effect' by ensuring that a lock release only triggers a single notification event rather than waking every waiting client.
2. B Because the ZooKeeper ZAB protocol prohibits a single Znode from having more than three active watch triggers registered concurrently.
3. C To ensure that the client can verify the geographical location of the specific replica that previously held the lock.
4. D It is a performance optimization to allow the leader node to batch session heartbeats with lock release events.