Which command creates a Docker registry secret named quayio for the server quay.io with user1 and pw123?

• A. oc secrets link default quayio --for pull
• B. oc delete secret quayio
• C. oc secrets link builder quayio
• D. oc create secret docker-registry quayio --docker-server quay.io --docker-username user1 --docker-password pw123

Answer: (D)

Creating a docker-registry secret stores credentials OpenShift uses to authenticate to a private registry when pulling images. The correct command creates a secret of type docker-registry named quayio with the registry server quay.io and the provided login details, exactly matching the required parameters: --docker-server quay.io, --docker-username user1, and --docker-password pw123. This sets up the credentials in the cluster so pods can pull images from quay.io. The other options either delete a secret, link an existing secret to a service account, or link to a different service account, but they do not create this new secret with the specified credentials.