You are designing a physician portal app in Node.js. This application will be used in hospitals and clinics that might have intermittent internet connectivity. If a connectivity failure occurs, the app should be able to query the cached data. You need to ensure that the application has scalability, strong consistency, and multi-region replication. What should you do?

A. Use Firestore and ensure that the PersistenceEnabled option is set to true. B. Use Memorystore for Memcached. C. Use Pub/Sub to synchronize the changes from the application to Cloud Spanner. D. Use Table.read with the exactStaleness option to perform a read of rows in Cloud Spanner.