How can the company increase resilience for this application?

Explanations:

Deploying a copy of the application in another AWS account does not inherently increase resilience for the application running in a specific AWS Region. While using multiple accounts can enhance security and manageability, it does not provide redundancy or failover capabilities within the same Region.

Deploying the application using multiple VPCs can help in segmenting resources for security and organizational purposes, but it does not directly increase resilience. Each VPC is isolated, and having multiple VPCs does not provide redundancy against failures in a specific VPC.

Deploying the application using multiple subnets within a single Availability Zone does not increase resilience. While subnets can help with network organization and security, if the Availability Zone experiences an outage, all subnets within that zone would also be affected.

Deploying the application using multiple Availability Zones (AZs) increases resilience significantly. It ensures that if one Availability Zone goes down, the application can continue to operate from another AZ, providing high availability and failover capabilities.