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.