Design a highly available Azure SQL database that meets these requirements: failover between replicas must occur without any data loss, the database must remain available during an availability zone outage, and costs must be minimized. Which Azure SQL deployment option best meets these requirements?

The Azure SQL Database Business Critical service tier provides high availability and automatic failover with no data loss, using multiple synchronous replicas within an availability zone and asynchronous replicas across zones. This architecture ensures availability during an availability zone outage. While not the absolute lowest cost, it offers the best balance of features for the given requirements compared to other options. The Basic and Standard tiers do not guarantee no data loss on failover and have less robust availability features. Azure SQL Managed Instance (General Purpose) also does not guarantee zero data loss and is typically more expensive than Azure SQL Database for similar performance.