The task is as follow:

Green foods has 5 canteens and each canteen has a manger and an assistant. Each staff will be assigned a PC and all PC will be linked together and have internet access. Design a network using either a single LAN, 5 LANs or 5 VLANs? Present all your arguments in support of and against your choice.

My initial approach is that 5VLAN's would be the most cost effective in terms of hardware, the question says that the PC's are all linked and require internet access, so VLAN's would be OK if the canteens are all on the same location/campus. If however the canteens are in different geographical then I would need 5 LAN,s, I maybe misunderstanding something very basic here, LAN's (local are network) generally only cover one building/campus is that right?

If I consider the VLAN option how many switches will I need, does each PC need to be connected to a separate switch interface, I understood that the benefit of a VLAN is that multiple LAN's can be configured on the same interface, once again a gap in my understanding, this applies to router interfaces ?

Any direction or thoughts would be greatly appreciated.