Answer: Cloud SQL, Cloud Spanner

The correct answers are **A (Cloud SQL)** and **B (Cloud Spanner)**. - **Cloud SQL** is chosen because it is a relational and transactional database. - **Cloud Spanner** is selected for its relational and transactional capabilities, along with its global scalability. **Why not the others?** - **BigQuery (C)** is not suitable for transactional systems. - **Cloud Bigtable (D)** offers transactional support but lacks relational features. - **Cloud Datastore (E)** is not designed as a relational data storage system. For more details, refer to the [GCP documentation on Storage Options](https://cloud.google.com/storage-options).

Author: LeetQuiz Editorial Team