You are designing a strategy for synchronizing two geographically disparate SQL Azure databases. A database named DB1 is located in North America. A database named DB2 is located in Asia. DB2 contains a subset of the tables in DB1. You need to recommend an approach for bidirectionally synchronizing the databases each day. What should you recommend？（）
- A Use SQL Azure Data Sync.
- B Use custom Microsoft Sync Framework metadata.
- C Use a Microsoft Sync Framework Partial Participant.
- D Use a Microsoft Sync Framework file synchronization provider.