You have a regional Spanner instance with no autoscaler that is serving a production workload. You observed a surge in write activities to the database during an ongoing promotional event. You received an alert that the database is close to the storage limit. Based on the storage utilization trend, the database will run out of storage in the next few hours. You want to resolve this issue as soon as possible. What should you do?

A. Create a custom instance configuration and add a custom read-only replica to the Spanner instance. B. Increase the compute capacity of the Spanner instance. C. Move the Spanner instance to a multi-regional configuration. D. Archive and delete historical data from the database.