B and C are the correct options. Using the Kubernetes Metrics Server (B) enables horizontal pod autoscaling to dynamically scale pods based on CPU/memory usage. This allows scaling at the application tier level. The Kubernetes Cluster Autoscaler (C) automatically adjusts the number of nodes in the EKS cluster in response to pod resource requirements and events. This allows scaling at the infrastructure level.

K8S Metrics Server and Autoscaler => B and C

This is pretty straight forward. Use the Kubernetes Metrics Server to activate horizontal pod autoscaling. Use the Kubernetes Cluster Autoscaler to manage the number of nodes in the cluster.

Kubernetes Metrics Server https://docs.aws.amazon.com/eks/latest/userguide/metrics-server.html AWS Autoscaler https://docs.aws.amazon.com/eks/latest/userguide/autoscaling.html and https://github.com/kubernetes/autoscaler/blob/master/cluster-autoscaler/cloudprovider/aws/README.md

By combining the Kubernetes Cluster Autoscaler (option C) to manage the number of nodes in the cluster and enabling horizontal pod autoscaling (option B) with the Kubernetes Metrics Server, you can achieve automatic scaling of your EKS cluster and container applications based on workload demand. This approach minimizes operational overhead as it leverages built-in Kubernetes functionality and automation mechanisms.

b and c is right