It has become necessary to configure an existing serial interface to accept a second Frame Relay virtualcircuit.Which of the following processes are required to accomplish this task？（）

• A、configure static frame relay map entries for each subinterface network.
• B、remove the ip address from the physical interface
• C、create the virtual interfaces with the interface command
• D、configure each subinterface with its own IP address
• E、disable split horizon to prevent routing loops between the subinterface networks
• F、encapsulate the physical interface with multipoint PPP