The correct answer is A. Amazon DynamoDB. DynamoDB is a fast and flexible NoSQL database service that provides consistent single-digit millisecond latency for data retrieval. It is well-suited for applications that require high-performance data retrieval. In this scenario, the metadata about the files can be stored in a DynamoDB table with a primary key based on the metadata attributes. This would enable the organization to quickly query and retrieve metadata about the files in real-time, allowing users to efficiently browse metadata and select files for download.