You need to ensure high availability for a critical database. Which Cloud SQL configuration provides automatic failover?

Correct answer: High availability with regional replicas

Option D is correct because Cloud SQL's High Availability (HA) configuration uses a regional setup with a primary instance and a standby replica in a different zone within the same region, providing automatic failover if the primary becomes unavailable. Option A is incorrect because a single instance with backups allows data recovery but does not provide automatic failover; there is still downtime while a new instance is restored. Option B is incorrect because read replicas distribute read traffic but are not promoted automatically during a primary failure and do not serve as a failover target. Option C is incorrect because on-demand snapshots are point-in-time backups used for data recovery, not for automatic failover.