Explanation

Option B (Cloud Spanner) is the correct answer because:

• Global Consistency: Cloud Spanner provides strong global consistency across regions, which is essential for financial data where consistency is critical
• Multi-Region Deployment: Cloud Spanner supports leader configuration in one region (North America) with read-only replicas in other regions (Asia and Europe), providing low-latency access globally
• ACID Compliance: As a relational database, Cloud Spanner ensures ACID transactions across regions
• High Availability: Automatic failover and global replication ensure high availability

Why other options are incorrect:

• Option A (BigQuery): BigQuery is primarily an analytical data warehouse, not designed for transactional workloads with global consistency requirements
• Option C (Cloud SQL): While Cloud SQL supports read replicas, it doesn't provide the same level of global consistency and automatic failover as Cloud Spanner for multi-region deployments
• Option D (Cloud Bigtable): Cloud Bigtable is a NoSQL database optimized for high-throughput workloads but doesn't provide the same transactional consistency guarantees as Cloud Spanner

For financial data requiring global consistency with low-latency access across North America, Asia, and Europe, Cloud Spanner is the most appropriate choice.