Choose Option A.
Custom Metadata Configuration: The instances in your project have the custom metadata enable-oslogin set to FALSE. This indicates that Google Cloud Identity-Aware Proxy (IAP) is not enabled for these instances. With IAP disabled, you typically use SSH keys to authenticate.
Project-wide SSH Keys are Blocked: The project-wide SSH keys are blocked, so adding a public key to the project metadata won't work.
Third-Party Tool: The option doesn't involve setting any custom metadata or changing instance configurations. Instead, it suggests using the built-in gcloud compute ssh command, which simplifies the SSH process.
Cloud Shell: Opening the Cloud Shell provides you with an environment where the Google Cloud SDK is pre-installed, including the gcloud command-line tool. It eliminates the need to install any third-party tools on your local machine.