You have 100 GB in BigQuery that is rarely accessed (1–2x/year) and must be immutable for 3 years while minimizing storage cost. What should you do?

The correct option minimizes storage cost for rarely accessed, immutable data while maintaining queryability. Exporting to Cloud Storage Archive class is the most cost-effective storage for infrequent access. A locked retention policy ensures immutability for the required 3 years. Creating an external table allows BigQuery to query the data directly from Cloud Storage without re-importing, providing on-demand analytics. Option 1 (BigQuery table clone) and Option 2 (BigQuery table snapshot) keep the data within BigQuery storage, which is more expensive than Cloud Storage Archive for rarely accessed data. Neither inherently provides a locked retention policy for immutability. Option 3 (export to Cloud Storage Archive with versioning) is better for cost but versioning doesn't guarantee immutability against deletion or modification by an authorized user in the same way a locked retention policy does.