Answer: Amazon MemoryDB

## Explanation Amazon MemoryDB is the correct choice because: - **In-memory data store**: MemoryDB is specifically designed as an in-memory database service - **High availability**: It provides automatic failover and multi-AZ deployments - **Durability**: MemoryDB uses a distributed transactional log that persists data across multiple Availability Zones, ensuring data durability - **Caching and session management**: It's optimized for use cases like caching, session stores, and real-time applications **Why other options are incorrect:** - **Amazon Aurora**: A relational database, not primarily an in-memory data store - **Amazon ElastiCache (Memcached)**: While it's an in-memory cache, it doesn't provide built-in durability as data is lost on node failures - **Amazon EBS volumes**: Block storage service, not an in-memory data store MemoryDB combines the performance of in-memory caching with the durability of a database, making it ideal for applications requiring both high performance and data persistence.

Author: Ritesh Yadav