The correct answer is B because the signurl command generates a signed URL that includes authentication data, allowing access without a Google account. The -d option specifies the duration the URL remains valid, which is exactly what's needed here. For more details, refer to the GCP documentation on Cloud Storage gsutil signurl. Key options include -m for specifying the HTTP method (default is GET), -d for duration (default is 1 hour), and -p for the keystore password. The maximum allowed duration is 7 days.