Which Alibaba Cloud service is used for relational databases?

ApsaraDB RDS (Relational Database Service) is Alibaba Cloud's fully managed relational database service. It supports popular relational database engines including MySQL, PostgreSQL, Microsoft SQL Server, and MariaDB, handling administrative tasks such as patching, backups, scaling, and high availability.

A. ECS (Elastic Compute Service) provides virtual infrastructure/servers, not a managed relational database service.
B. OSS (Object Storage Service) provides unstructured object storage rather than relational database capabilities.
D. SLB (Server Load Balancer) distributes network traffic across backend instances for application availability.

- Alibaba Cloud Official Documentation, ApsaraDB RDS - Product Overview, Section: "What is ApsaraDB RDS?".

- Alibaba Cloud Relational Database Service User Guide, Section: "Supported Database Engines".