Refer to the exhibit. The serial link that connects the two offices has a bandwidth of 128 kbps.What could be done to set aside 64 kbps of bandwidth to transport VoIP traffic over the WAN link？（）

• A、apply the clock rate 64000 command on both serial interfaces connected to the WAN link
• B、apply the bandwidth 64 command on both serial interfaces connected to the WAN link
• C、apply the frame-relay voice-bandwidth 64000 command to enable the QoS Call Admission Control feature on the serial link
• D、apply the max-conn 64 command on a perial peer basis on both sides of the serial link
• E、apply the ip bandwidth-percent eigrp 1 64 command on both sides of the serial link
• F、apply the auto-cost reference-bandwidth 64 command on both sides of the serial link