They currently have transactional data stored on-premises in a PostgreSQL database and they want to modernize their database that supports transactional workloads and analytics .If they select cloud Sql (postgreSQL) it will minimize the cost and complexity. and for analytics purpose they can create federated queries over cloudSql(postgreSql) https://cloud.google.com/bigquery/docs/federated-queries-intro This approach will minimze the cost

B - minimize cost Cloud SQL for PostgreSQL: Generally less expensive than AlloyDB, especially for smaller deployments. AlloyDB: Can be significantly more expensive due to its advanced features and high performance capabilities.

minimize cost and complexity

Considering the cost factor, I'll go with D. If "minimize cost" is not present in the question, then I'd go with 'B' AlloyDB. Cloud SQL for PostgreSQL: Generally less expensive than AlloyDB. AlloyDB: Can be significantly more expensive due to its advanced features and high performance capabilities.

AlloyDB for PostgreSQL is a fully managed, PostgreSQL-compatible database service that's designed for your most demanding workloads, including hybrid transactional and analytical processing. ref: https://cloud.google.com/alloydb/docs/overview

https://cloud.google.com/alloydb#all-features The requirement is to minimize cost and complexity. Cloud SQL would be the best choice.

Database Migration Service makes it easier for you to migrate your data to Google Cloud. This service helps you lift and shift your PostgreSQL workloads into Cloud SQL.

- AlloyDB is a fully managed, PostgreSQL-compatible database service with industry-leading performance.

B. Migrate your workloads to AlloyDB for PostgreSQL.