Final answer:
The correct type of network for devices not adhering to NAC policies is a quarantine network, designed to keep potentially compromised devices isolated while still allowing for necessary access to resolve compliance issues.
Step-by-step explanation:
The type of network that would be set up in an office for computers and mobile devices that do not comply with the company's Network Access Control (NAC) policies is a quarantine network. A quarantine network is designed to restrict the access of non-compliant devices to sensitive resources, while still allowing them some level of network access so their compliance issues can be addressed. Such networks help maintain security by ensuring that devices that could potentially compromise the network are kept separate from the main network until they meet the required security standards. Other options like a guest network or a wireless network do not necessarily address compliance issues, and a VPN is typically used to securely connect remote users to the network, not to manage non-compliant devices.