Azure SQL Database, due to its built-in high availability and scalability features, including automatic failover and read replicas, which meet the requirements without additional configuration.

Azure Cosmos DB, for its global distribution and multi-region writes capability, which might exceed the specified requirements and increase costs unnecessarily.

Azure Database for MySQL, offering a managed MySQL service with high availability options, but may not fully support automatic failover as seamlessly as Azure SQL Database.

Azure Database for PostgreSQL, providing a managed PostgreSQL service with read replicas, yet it might not offer the same level of built-in high availability features as Azure SQL Database.