Your organization is a financial company that needs to store audit log files for 3 years. Your organization has hundreds of Google Cloud projects. You need to implement a cost-effective approach for log file retention. What should you do? 

Answer options:

A. Create an export to the sink that saves logs from Cloud Audit to BigQuery.
B. Create an export to the sink that saves logs from Cloud Audit to a Coldline Storage bucket.
C. Write a custom script that uses logging API to copy the logs from Stackdriver logs to BigQuery.
D. Export these logs to Cloud Pub/Sub and write a Cloud Dataflow pipeline to store logs to Cloud SQL.

A

Reference: https://cloud.google.com/logging/docs/audit/