Which service allows for the management of distributed in-memory cache environments?

Amazon ElastiCache is the correct choice for managing distributed in-memory caching environments. This service specifically provides caching capabilities to enhance the performance of applications by storing frequently accessed data in memory, which reduces the need for slower disk-based storage. ElastiCache supports popular caching engines like Redis and Memcached, allowing developers to create highly scalable and efficient caching solutions tailored to their applications' needs.

The other options serve different purposes. Amazon RDS is a managed relational database service, primarily used for managing traditional databases rather than caching layers. Amazon Neptune is a graph database service designed for applications that require relationships between data nodes, not for caching. Amazon EBS is a block storage service intended for use with Amazon EC2 instances, providing persistent storage for various applications but not specifically designed for in-memory caching. Therefore, ElastiCache stands out as the dedicated solution for distributed in-memory cache management.