Answer: Cloud SQL, Cloud Spanner

The correct answers are **B (Cloud SQL)** and **D (Cloud Spanner)**. - **Cloud SQL** is chosen because it is a relational and transactional database. - **Cloud Spanner** is selected for its global scalability, relational model, and transactional support. **Why not the others?** - **A (Cloud Bigtable)**: While it offers transactional support, it is not relational. - **C (BigQuery)**: It is not designed for transactional operations. - **E (Cloud Datastore)**: It does not support relational data storage. Refer to Google Cloud's documentation on Storage Options for more details.

Author: LeetQuiz Editorial Team