Correct Answer: C. Cloud Spanner

• A. Cloud Firestore is incorrect because it is a NoSQL document database, not a relational database, which is required for this scenario.
• B. Cloud SQL is incorrect because it is a regional service that requires manual configuration changes to scale and is not globally distributed.
• C. Cloud Spanner is correct because it is a globally distributed, horizontally scalable, and strongly consistent relational database service. It automatically scales with user growth without the need for manual configuration changes, making it ideal for global workloads.
• D. Cloud Datastore is incorrect because it is a NoSQL document database and a predecessor to Cloud Firestore, not suitable for relational database requirements.

For more information, visit:

• Cloud Spanner
• Cloud Datastore
• Cloud Firestore
• Cloud SQL