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 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 DHCP address pool has been exhausted.
B . VLSM is misconfigured between the router interface and the DHCP pool.
C . The ip helper-address command is missing on the R2 interface that connects to the switch.
D . Interface ports are shutdown on the remote server.

Answer: B