The correct answer is C because enabling node auto-upgrades ensures that your Kubernetes cluster's nodes are automatically updated to the latest stable version of Kubernetes without requiring manual intervention. This feature leverages the same update mechanism as manual upgrades but automates the process, reducing management overhead and enhancing security by promptly applying updates that may include critical security patches. It also simplifies the maintenance of your cluster by keeping it up-to-date with the latest Kubernetes features. Node auto-repairing (Option B) focuses on maintaining node health rather than handling upgrades, while manually applying security patches (Option A) or always using the latest version at creation (Option D) does not provide the automated, ongoing update mechanism that auto-upgrades offer.