What device connects multiple devices within a network?

A switch is the correct answer because it is specifically designed to connect multiple devices within a local area network (LAN). It operates at the data link layer of the OSI model, allowing devices such as computers, printers, and servers to communicate with one another efficiently. The switch uses MAC addresses to forward data only to the intended recipient device, maximizing network performance and reducing unnecessary traffic.

In contrast, a router serves a different purpose by connecting multiple networks together, such as a local network to the internet. A modem acts as a bridge between the internet and a local network, modulating and demodulating signals for data transmission. A firewall is primarily a security device that monitors and controls incoming and outgoing network traffic based on predetermined security rules. Each of these devices plays a critical role in networking but does not connect multiple devices within a single network like a switch does.