The correct answer is Option C. To deploy a Docker container on Kubernetes Engine, you should first create a Docker image from the Dockerfile and push it to Container Registry, which is a fully-managed Docker container registry that makes it easy for you to store, manage, and deploy Docker container images. Then, you can create a Deployment YAML file that specifies the image to use and other desired deployment options, and use the kubectl command-line tool to create the deployment based on the YAML file. Option A is incorrect because kubectl app deploy is not a valid command. Option B is incorrect because gcloud app deploy is used to deploy applications to App Engine, not Kubernetes Engine. Option D is incorrect because it involves storing the image in Cloud Storage rather than Container Registry.