A user cannot access any local or remote resources.

The best answer is E. Subnet mask. With the current subnet mask of 255.255.255.0, the user’s IP address 192.168.1.10 is on the 192.168.1.0/24 network, while the default gateway 192.168.2.1 is on the 192.168.2.0/24 network. A host normally needs its default gateway to be reachable on the same local network. The Mike Meyers material explains that the subnet mask identifies the network ID and host ID, and every computer on a single LAN must have the same network ID. With 255.255.255.0, the first three octets define the network, so 192.168.1.x and 192.168.2.x are different networks. The NOC verified that the gateway value itself is correct, so changing the gateway would conflict with the verified next hop. DNS settings would affect name resolution, not access to all local and remote resources. Lease time and firewall rules are not indicated by the IP information. The subnet mask must be changed so the client and gateway are in the same local IP network.