Which Redis feature provides an append-only, replayable event log with consumer groups?

1. A Pub/Sub
2. ✓ B Streams (XADD / XREADGROUP) (correct answer)
3. C Lists
4. D Keyspace notifications

Shortcut: Streams persist entries and support consumer groups with acknowledgement and pending-entry tracking. Pub/Sub is fire-and-forget with no persistence or redelivery.