The correct answer is Running redundant control plane components on several separate nodes.

Running redundant control plane components on several separate nodes is the strongest practice for continuous availability because it removes single points of failure and allows the control plane to tolerate one or more node failures while continuing to serve the cluster. Distributing API server instances and etcd members across multiple machines preserves quorum and enables leader election and failover so the cluster can remain functional during maintenance or hardware outages.

Reducing the number of control plane nodes to simplify management is incorrect because fewer nodes increase the risk of a single point of failure and make it harder to maintain quorum for etcd. Simplifying management by cutting nodes reduces availability and fault tolerance.

Isolating control plane nodes at the network level is incorrect because network isolation can improve security but it does not by itself provide redundancy or quorum. Isolation can even make recovery harder if it increases the chance of network partitions that interrupt control plane communication.

Google Kubernetes Engine is incorrect for this question because it names a managed product rather than a practice. GKE can provide a highly available control plane as a service in many cases but the question asks for the practice that most strongly supports continuous availability in a production cluster.

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