What type of database is Amazon RDS?

Amazon RDS, or Amazon Relational Database Service, is designed specifically to manage relational databases, which organize data into structured formats using tables. This service allows for easy setup, operation, and scaling of relational databases in the cloud, supporting multiple database engines like MySQL, PostgreSQL, Oracle, MariaDB, and Microsoft SQL Server.

The strength of RDS lies in its capability to handle structured data, enforce relationships between data with foreign keys, and support complex queries through SQL (Structured Query Language). By using RDS, users benefit from automated backups, patch management, and replication, significantly simplifying the operational burden associated with running relational databases.

In contrast, the other options represent different types of database services. A NoSQL database service typically handles unstructured or semi-structured data and is not based on the relational model. A document database service stores data in documents, which may not follow a consistent schema. A time series database service is specially designed to handle time-stamped data and is optimized for querying time-series data efficiently. These differences highlight why the correct answer is centered on the relational approach of Amazon RDS.