Which of the following is an unlikely reason for the ARP process to fail？（）

• A、CEF switching is disabled on the switch
• B、The source device and destination device are in different VLANs
• C、The VLAN is excluded from the trunk
• D、The host is connected to the switch through an IP phone
• E、A faulty cable from host to switch or between switches
• F、The trunking encapsulation type is inconsistent on the two ends of the link