An application uses an RDS for MySQL Single-AZ DB instance. It needs managed automatic failover after an Availability Zone failure. It does not need additional read capacity. Which change meets these requirements with the least database administration?

1. Convert the database to a Multi-AZ DB instance deployment with one standby instance.
2. Take a manual snapshot before each business day.
3. Create a same-Region read replica and require an operator to promote it after failures.
4. Increase the backup retention period without changing the Single-AZ deployment.