Design a highly available Azure SQL database subject to these requirements: failover must occur without data loss; the database must remain available during a zone outage; and cost should be minimized. Which deployment option is most appropriate?

Azure SQL Database Premium (or Business Critical) is the correct choice because it offers zone-redundant high availability, ensuring the database remains available during a zone outage and guarantees no data loss during failover. This tier uses multiple replicas across availability zones, providing RPO (Recovery Point Objective) of zero. While it might seem more expensive initially than other options, it minimizes overall cost by preventing data loss and extended downtime, which can be far more costly in a business-critical scenario. Azure SQL Database Standard and Serverless tiers do not offer zone redundancy for high availability, making them unsuitable for the zone outage requirement. Azure SQL Managed Instance General Purpose also lacks zone redundancy.