The suggested answer is A, D, E.
Within the Kubernetes control plane, there are specific components designed to manage the cluster's state and provide operational functions. The scheduler balances pods across the nodes within a Kubernetes cluster, ensuring optimal resource utilization and pod placement. The etcd component stores Kubernetes cluster data in a key-value data store and serves as the cluster’s primary datastore. The controller manager watches the API for changes and responds with appropriate actions to maintain the desired state of the system. Hence, the functions of balancing pods, storing cluster data, and watching the API for changes are all crucial roles provided by the control plane components.