You are working at a financial institution that stores mortgage loan approval documents on Cloud Storage. Any change to these approval documents must be uploaded as a separate approval file, so you want to ensure that these documents cannot be deleted or overwritten for the next 5 years. What should you do? 

Answer options:

A. Create a retention policy on the bucket for the duration of 5 years. Create a lock on the retention policy.
B. Create the bucket with uniform bucket-level access, and grant a service account the role of Object Writer. Use the service account to upload new files.
C. Use a customer-managed key for the encryption of the bucket. Rotate the key after 5 years.
D. Create the bucket with fine-grained access control, and grant a service account the role of Object Writer. Use the service account to upload new files.

A

Reference: https://cloud.google.com/storage/docs/using-bucket-lock