Which AWS service would support this workload?

Explanations:

Amazon RDS (Relational Database Service) is designed to manage relational databases, including MySQL. It simplifies database setup, management, and scaling in the cloud, making it the ideal choice for running a copy of a MySQL database.

Amazon Neptune is a fully managed graph database service, not suitable for MySQL databases. It is specifically optimized for graph applications and does not support traditional relational database structures.

Amazon ElastiCache for Redis is a managed caching service for Redis and Memcached. It is not intended for relational databases like MySQL, but rather for in-memory data storage and caching to enhance application performance.

Amazon Quantum Ledger Database (Amazon QLDB) is a fully managed ledger database designed for applications requiring a transparent, immutable, and cryptographically verifiable transaction log. It is not compatible with MySQL and is not designed for relational data.