Which AWS service provides compatibility with MongoDB?

The correct answer is DocumentDB, which is specifically designed to be compatible with MongoDB applications. DocumentDB enables users to set up, operate, and scale a fully managed document database service that supports MongoDB workloads. This compatibility means that existing MongoDB applications can be easily migrated to DocumentDB without significant changes to the application code.

This service provides the necessary features such as support for the MongoDB API, which includes document data models and querying mechanisms, allowing developers to leverage their skills and tools developed around MongoDB directly within AWS.

The other services listed serve different purposes: Neptune is a graph database service designed for handling highly connected datasets, Keyspaces is a managed service for Apache Cassandra, focusing on wide-column store capabilities, and Redshift is a data warehousing solution intended for large-scale data analytics. None of these services are tailored for compatibility specifically with MongoDB, unlike DocumentDB.