You have a web application that publishes messages to Pub/Sub. You plan to build new versions of the application locally and want to quickly test Pub/Sub integration for each new build. How should you configure local testing?

A. Install Cloud Code on the integrated development environment (IDE). Navigate to Cloud APIs, and enable Pub/Sub against a valid Google Project ID. When developing locally, configure your application to call pubsub.googleapis.com. B. Install the Pub/Sub emulator using gcloud, and start the emulator with a valid Google Project ID. When developing locally, configure your application to use the local emulator with ${gcloud beta emulators pubsub env-init}. C. In the Google Cloud console, navigate to the API Library, and enable the Pub/Sub API. When developing locally, configure your application to call pubsub.googleapis.com. D. Install the Pub/Sub emulator using gcloud, and start the emulator with a valid Google Project IWhen developing locally, configure your application to use the local emulator by exporting the PUBSUB_EMULATOR_HOST variable.