In Kafka Streams, what is the role of a changelog-backed state store?

In Kafka Streams, what is the role of a changelog-backed state store?

• A. They store only metadata about the topology.
• B. They are used for transient, non-persistent data.
• C. They hold the input data before processing.
• D. They provide fault-tolerant persistence for stateful operators by writing changes to a changelog topic.

Answer: (D)