Here are the changes to the code if you make those replacements:
Step 1b: Assign the third subnet to the LAB 124-C LAN.
Step 1c: Assign the first network host address (the lowest) in this subnet to the G0/0 interface on CS Department.
Step 1d: Starting with the fourth subnet, subnet the network again so that the new subnets will provide 14 host addresses per subnet while wasting the fewest addresses.
Step 1f: Assign the first address (the lowest) in the LAB 214-A LAN subnet to the G0/1 interface of the CS Department router.
The rest of the code would remain the same. Let me know if you