A live TV show asks viewers to cast votes using their mobile phones. The event generates a large volume of data during a 3-minute period. You are in charge of the "Voting infrastructure" and must ensure that the platform can handle the load and that all votes are processed. You must display partial results while voting is open. After voting closes, you need to count the votes exactly once while optimizing cost. What should you do?

A. Create a Memorystore instance with a high availability (HA) configuration. B. Create a Cloud SQL for PostgreSQL database with high availability (HA) configuration and multiple read replicas. C. Write votes to a Pub/Sub topic and have Cloud Functions subscribe to it and write votes to BigQuery. D. Write votes to a Pub/Sub topic and load into both Bigtable and BigQuery via a Dataflow pipeline. Query Bigtable for real-time results and BigQuery for later analysis. Shut down the Bigtable instance when voting concludes.