Your network contains the servers shown in the following table. Server name S erver role Server location Server share Server1 File server Office1 Data1 Server2 File server Office2 Data2 Office1 and Office2 connect to each other by using a WAN link. Users in Office2 frequently access the same set of files stored in Data1. You need to reduce the amount of file transfer traffic across the WAN link. What should you add to Server1?（）

• A、the Background Intelligent Transfer Service (BITS) feature
• B、the BranchCache feature
• C、the BranchCache for network files role service
• D、the Distributed File System (DFS) role service