You are designing a web service that will be hosted in Windows Azure.  The web service will accept and store structured and semi-structured data. The web service must meet the following requirements：   - Update all data within a single transaction.  - Enforce the data structure for structured data within the data store.    You need to recommend an approach for storing the data.  What should you recommend？（）

• A、 Use Windows Azure Queues.
• B、 Use a single SQL Azure database.
• C、 Use a single Windows Azure Drive.
• D、 Use Windows Azure Table storage.