Which of these systems is a famous user of Consistent Hashing?

1. A The core logic of Redis Cluster, which uses a simplified hash-slot mapping to manage its distributed data partitioning.
2. B The local storage engine of SQLite, which uses hashing to optimize the search for records within a single database file.
3. C A standard PHP Session handler, which traditionally uses a fixed round-robin approach to distribute user data across file volumes.
4. D Discord's Gateway Service, which uses it to route millions of concurrent users to the correct real-time voice and message nodes.