Answer: Configure a Cloud SQL for PostgreSQL instance with high availability enabled.

The correct answer is **B. Configure a Cloud SQL for PostgreSQL instance with high availability enabled.** 1. **ACID-compliance**: PostgreSQL is renowned for its strong adherence to ACID principles (Atomicity, Consistency, Isolation, Durability), ensuring data integrity and consistency, which is crucial for the system in question. 2. **High availability**: Enabling high availability in Cloud SQL for PostgreSQL means the database is replicated across multiple zones within a region. This setup provides redundancy and fault tolerance, allowing the system to automatically failover to another zone in case of a failure, thereby minimizing the need for human intervention and ensuring continuous operation. **Why other options are less suitable**: - **A. Set up a BigQuery table with a multi-region configuration**: BigQuery, while excellent for analytics and scalable data warehousing, does not offer the transactional support or ACID compliance required by the system. - **C. Configure a Bigtable instance with more than one cluster**: Bigtable is a NoSQL database designed for scalability and high throughput, not for ACID compliance or automatic failover capabilities. - **D. Configure a Cloud SQL for MySQL instance with point-in-time recovery enabled**: While point-in-time recovery aids in data restoration, it does not ensure high availability or automatic failover, and MySQL's ACID compliance may not be as robust as PostgreSQL's. In summary, option B is the optimal choice, combining PostgreSQL's ACID compliance with Cloud SQL's high availability features to meet the system's requirements effectively with minimal human intervention during failures.

Author: LeetQuiz Editorial Team