What is the primary role of the Kubernetes API server?

Correct answer: Process and respond to requests from clients to manage cluster resources

Option D is correct because the Kubernetes API server is the central control-plane component that exposes the Kubernetes API, validates and processes RESTful requests from clients such as kubectl and controllers, and updates the desired state stored in etcd. Option A is wrong because storing cluster data is the role of etcd, which is a separate key-value store; the API server reads and writes to etcd but is not itself the storage layer. Option B is wrong because running containerized workloads on worker nodes is performed by the kubelet and the container runtime on each node, not the API server. Option C is wrong because enforcing network policies is handled by the network plugin (CNI) and the kube-proxy or policy controllers, not directly by the API server.