A company runs a stateful production application on Amazon EC2 instances that requires at least two EC2 instances to always be running. A solutions architect must design a highly available, fault-tolerant architecture and creates an Auto Scaling group of EC2 instances. Which additional steps should the architect take to meet these requirements?

The correct option ensures high availability and fault tolerance for a stateful application requiring at least two instances. Setting the minimum capacity to four and distributing two On-Demand instances across two Availability Zones (AZs) provides redundancy. If one instance fails, or an entire AZ experiences an outage, two instances will still be running in the other AZ, exceeding the minimum requirement of two. On-Demand instances are suitable for stateful production applications due to their consistent availability. The first incorrect option (minimum capacity two, one instance per AZ) fails to meet the "at least two instances always running" requirement if one AZ fails. The third incorrect option uses Spot Instances, which are unsuitable for stateful production applications due to potential interruptions. The fourth incorrect option also uses Spot Instances, introducing unreliability for a critical application.