An ISP technician gets a call from a business that just changed equipment but can no longer connect to the Internet. The technician checks the ARP table on the ISP switch, and there is no corresponding MAC address present. Instead, the entry is Incomplete. Which of the following could cause this condition? 

Answer options:

A. VLAN mismatch
B. Duplex/Speed mismatch
C. Duplicate IP address
D. TX/RX reverse

B