What is the most likely reason that the other users are experiencing connection failure?

Refer to the exhibit.

Users in your office are complaining that they cannot connect to the servers at a remote site. When you troubleshooting you find that you can successfully reach the servers from router R2.

What is the most likely reason that the other users are experiencing connection failure?
A . The ip helper-address command is missing on the R2 interface that connects to the switch
B . Interface ports are shut down on the remote servers
C . VLSM is misconfigured between the router interface and the DHCP pool
D . The DHCP address pool has been exhausted

Answer: C