An organization has an ecommerce application that requires a cost-effective, transactional database.

The correct answer is C. Cloud SQL. Here's why:

Context of the Question: The organization needs a cost-effective, transactional database for an e-commerce application serving customers in a single region. A transactional database is needed to handle online transactions with ACID (Atomicity, Consistency, Isolation, Durability) properties.

Google Cloud Product Relevance:

Cloud SQL is a fully managed relational database service for MySQL, PostgreSQL, and SQL Server. It is cost-effective, supports transactional workloads, and is suitable for applications with regional data residency requirements. This makes it ideal for an e-commerce application that only serves customers in a single region.

Why Not Other Options:

A. Cloud Spanner: Cloud Spanner is a globally distributed, strongly consistent database designed for large-scale, mission-critical applications. It is more expensive and better suited for applications requiring global distribution and high availability across multiple regions.

B. Cloud Bigtable: Cloud Bigtable is a NoSQL wide-column database designed for low-latency, high-throughput workloads, such as analytics. It does not support ACID transactions, making it unsuitable for transactional workloads like an e-commerce application.

D. BigQuery: BigQuery is a fully managed data warehouse designed for large-scale analytics. It is not suitable for transactional database needs.

Google Cloud Digital Leader References:

For more details on Cloud SQL, refer to the Cloud SQL documentation in the Google Cloud platform.