The correct answer is Managed NoSQL Database Service. Managed NoSQL Database Services in the cloud are designed to provide high availability and fault tolerance for non-relational databases. They are well-suited for handling unstructured data and can scale to meet high read and write demands, which are fundamental requirements in this particular scenario. In contrast, Relational Database Service would not be suitable since it is optimized for structured data with defined relationships. File Storage Service is incorrect as it is intended for storing files and not for database operations. Lastly, Block Storage Service is also not suitable because it's typically used for databases that require a fixed size of storage and low latency, not for databases with high scalability and unstructured data like NoSQL.