A network administrator has been receiving work orders about poor voice quality crossing a branch T1.
The cause is determined to be users running high bandwidth file sharing applications across the T1
sending large packets delaying the smaller voice streams.
Which of the following would improve voice quality?（）

A.Configure traffic shaping to reduce the bandwidth available to the file sharing application.
B.Configure a separate VLAN for the IP phones.
C.Install a content caching proxy at the branch to reduce inbound WAN traffic.
D.Upgrade switches to provide higher bandwidth ports for workstations and IP phones.