The correct answer is C, Amazon Aurora. Amazon Aurora is a relational database service provided by AWS that is compatible with MySQL and PostgreSQL. It is designed to deliver high performance, scalability, and availability, and is fully managed by AWS. Aurora is built for the cloud and offers the performance and availability of commercial-grade databases at a lower cost. It supports automatic failover and self-healing storage, and provides an additional security layer by encrypting data in transit and at rest. Amazon Redshift (A) is a data warehouse service for big data analytics, Amazon DynamoDB (B) is a NoSQL database service designed for high write and read throughput, and Amazon Neptune (D) is a graph database service for storing and querying highly connected data.