What Would Happen to an RDS (Relational Database Service) Multi-Availability

Multiple Choice

What would happen to an RDS (Relational Database Service) multi-Availability Zone deployment if the primary DB instance fails?

A) The IP of the primary DB Instance is switched to the standby DB Instance.
B) A new DB instance is created in the standby availability zone.
C) The canonical name record (CNAME) is changed from primary to standby.
D) The RDS (Relational Database Service) DB instance reboots.