Which AWS database service provides in-memory data storage?

Explanations:

Amazon DynamoDB is a fully managed NoSQL database service that provides fast and predictable performance with seamless scalability but does not specifically offer in-memory data storage.

Amazon ElastiCache is a fully managed in-memory data store compatible with Redis and Memcached, specifically designed for caching and in-memory data storage.

Amazon RDS (Relational Database Service) is a managed relational database service that supports several database engines, but it is not primarily focused on in-memory data storage.

Amazon Timestream is a time series database service designed for IoT and operational applications; it does not provide in-memory storage capabilities.