Your application images are built and pushed to Google Container Registry (GCR). You want to build an automated pipeline that deploys the application when the image is updated while minimizing the development effort. What should you do?

A. Use Cloud Build to trigger a Spinnaker pipeline. B. Use Cloud Pub/Sub to trigger a Spinnaker pipeline. C. Use a custom builder in Cloud Build to trigger Jenkins pipeline. D. Use Cloud Pub/Sub to trigger a custom deployment service running in Google Kubernetes Engine (GKE).