Which of the following devices on a home network should be placed in a DMZ?

A backup server stores sensitive internal data and should remain fully protected behind the internal firewall - placing it in a DMZ would expose critical data to unnecessary risk.

A gaming server hosted at home requires inbound connections from external Internet users or gaming platforms to function as a multiplayer host. Placing it in the DMZ exposes it directly to the Internet (or with minimal firewall restriction) without exposing the rest of the internal network, which is the intended purpose of a DMZ.

A smartphone is a client device that initiates outbound connections - it does not need to accept inbound connections from the Internet and should not be in a DMZ.

A wireless printer is an internal resource used only by devices on the local network - it does not require Internet-facing exposure and should remain on the internal network.