Which option meets the requirement of your team?

An application running on a Compute Engine instance needs to read data from a Cloud Storage bucket. Your team does not allow Cloud Storage buckets to be globally readable and wants to ensure the principle of least privilege.

Which option meets the requirement of your team?
A . Create a Cloud Storage ACL that allows read-only access from the Compute Engine instance’s IP address and allows the application to read from the bucket without credentials.
B . Use a service account with read-only access to the Cloud Storage bucket, and store the credentials to the service account in the config of the application on the Compute Engine instance.
C . Use a service account with read-only access to the Cloud Storage bucket to retrieve the credentials from the instance metadata.
D . Encrypt the data in the Cloud Storage bucket using Cloud KMS, and allow the application to decrypt the data with the KMS key.

Answer: C

Explanation:

If the environment variable GOOGLE_APPLICATION_CREDENTIALS is set, ADC uses the service account key or configuration file that the variable points to. If the environment variable GOOGLE_APPLICATION_CREDENTIALS isn’t set, ADC uses the service account that is attached to the resource that is running your code.

https://cloud.google.com/docs/authentication/production#passing_the_path_to_the_service_account_key_in_code