A server is connected to a gigabit Ethernet switch and has negotiated 1Gbps / Full Duplex. When transferring large files to and from other servers on the segment via FTP slow performance is noticed.All network cabling，network hardware and server hardware were verified to be working correctly.  Which of the following could be done to improve performance？（）

• A、 Decrease the TCP window size.
• B、 Increase the UDP window size.
• C、 Increase the TCP window size.
• D、 Decrease the UDP window size.