Which AWS database service providers in-memory data storage?

Explanations:

Amazon DynamoDB is a NoSQL database service that provides fast and predictable performance, but it is not primarily an in-memory data storage solution. It stores data on disk and offers caching features.

Amazon ElastiCache is specifically designed for in-memory data storage, providing caching capabilities using Redis or Memcached to improve application performance.

Amazon RDS (Relational Database Service) is a managed relational database service that stores data on disk and is not designed for in-memory storage.

Amazon Timestream is a time series database service optimized for time-stamped data, and it uses disk storage for its data management, not primarily in-memory storage.