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?（）
- AThe Ethernet interface should have keepalives enabled.
- BThe duplex settings are wrong on the Ethernet interface.
- CThe qos pre-classify command should be removed from the tunnel interfaces.
- Dthe priority queue for the voice class is probably taking all the bandwidth.
- Ethere are probably not enough interface buffers；they should be tuned.