Which example best demonstrates vertical scaling?

Installing more memory in an existing VM is the best example of vertical scaling (scaling up). Vertical scaling involves increasing the resources (CPU, RAM, disk I/O) of an existing server or virtual machine to handle increased load. Adding 5 VMs behind a load balancer is an example of horizontal scaling (scaling out), where you add more instances to distribute the load. Using a CDN for edge delivery improves content delivery speed and reduces origin server load but isn't a direct scaling method for compute resources. Creating a backup region is for disaster recovery and business continuity, not a scaling strategy for performance.