Which device type connects two or more local area networks (LANs) together?

The correct answer is a router because a router is specifically designed to connect multiple local area networks (LANs) together, facilitating communication between them. It can route data from one network to another, determining the best path for data packets to travel. This capability is essential for integrating separate networks, such as connecting different office locations or linking a home network to the internet.

In contrast, a switch operates within a single local area network, managing data traffic between devices on that network without connecting to other networks. A hub also connects devices within a single network but does so by broadcasting data to all connected devices, making it less efficient than a switch. A modem primarily serves to connect a network to the internet by translating digital data from a computer into a format suitable for transmission over telephone lines or cable systems, but it does not connect multiple LANs directly.