What are the Differences Between VPA, HPA, CA, and CPA in Kubernetes?

Kubernetes offers various automatic scaling mechanisms like Horizontal Pod Autoscaler (HPA), Vertical Pod Autoscaler (VPA), Cluster Propotional Autoscaler (CPA), and Cluster Autoscaler (CA). HPA adjusts the number of Pod replicas based on resource usage metrics, VPA adjusts the resource usage of individual instances, CPA scales the number of Pod replicas based on the cluster's scale, and CA dynamically adjusts the number of nodes based on specific conditions.