You are using App Engine and Cloud SQL for PostgreSQL to develop an application. You want to test your application code locally before deploying new application versions to the development environment that is shared with other developers. You need to set up your App Engine local development environment to test your application while keeping all traffic to Cloud SQL instances encrypted and authenticated to Cloud IAM and PostgreSQL. What should you do before starting the local development server?

A. Install PostgreSQL on your local workstation. Run a local PostgreSQL database on your workstation. Configure the application to connect to a PostgreSQL instance on localhost. B. Download and install the Cloud SQL Auth Proxy to your local development environment. Configure the Cloud SQL Auth Proxy to connect to the Cloud SQL instance and run the proxy. Configure the application to connect to a PostgreSQL instance on localhost. C. Deploy a Compute Engine instance, and install HAProxy on the instance. Configure Cloud SQL Auth Proxy on the instance, and use the instance’s service account to authenticate to Cloud SQL. Configure the application to connect to the Compute Engine instance's IP address. D. Configure your local development server to connect to the private IP address of the Cloud SQL instance. Encrypt database entries with a cryptographic library before submitting them to the database. Store the decryption key as an environment variable in App Engine.