A Company Runs a Web Service on Amazon EC2 Instances

A company runs a web service on Amazon EC2 instances behind an Application Load Balancer. The instances run in an Amazon EC2 Auto Scaling group across two Availability Zones. The company needs a minimum of four instances at all times to meet the required service level agreement (SLA) while keeping costs low. If an Availability Zone fails, how can the company remain compliant with the SLA?

A) Add a target tracking scaling policy with a short cooldown period.
B) Change the Auto Scaling group launch configuration to use a larger instance type.
C) Change the Auto Scaling group to use six servers across three Availability Zones.
D) Change the Auto Scaling group to use eight servers across two Availability Zones.