Which of these is not a reason a Multi-AZ RDS instance …

Which of these is not a reason a Multi-AZ RDS instance will failover?

A.
An Availability Zone outage

B.
A manual failover of the DB instance was initiated using Reboot with failover

C.
To autoscale to a higher instance class

D.
The primary DB instance fails

Explanation:
The primary DB instance switches over automatically to the standby replica if any of the > following conditions occur: An
Availability Zone outage, the primary DB instance fails, the DB instance’s server type is changed, the operating system
of the DB instance is, undergoing software patching, a manual failover of the DB instance was initiated using Reboot with
failover.
http://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/Concepts.MultiAZ.html