Refer to the exhibit. You would like to guarantee 7 Mb/s for FTP traffic in your LAN, as it seems that peer-to-peer traffic is taking up a large amount of bandwidth. When testing the configuration, you notice that FTP traffic doesn't reach 7 Mb/s. What is the problem?（）

A.The Ethernet interface should have keepalives enabled.
B.The duplex settings are wrong on the Ethernet interface.
C.The qos pre-classify command should be removed from the tunnel interfaces.
D.the priority queue for the voice class is probably taking all the bandwidth.
E.there are probably not enough interface buffers；they should be tuned.