The correct answer is B, Amazon DynamoDB. It is a fully managed NoSQL database service provided by AWS that allows users to store and retrieve any amount of data. DynamoDB is designed to handle large amounts of data with high read and write throughput, making it ideal for various use cases such as gaming, ad tech, IoT, and mobile applications. As a fully managed service, DynamoDB takes care of the infrastructure management, including hardware provisioning, database setup, scaling, and patching, which means users do not have to manage the underlying hardware or database software themselves.