What type of address is used to identify a device on a local network?

A MAC address is used to identify a device on a local network. It is a hardware identifier that is assigned to a network interface card (NIC) and is unique to each device within that local network. The MAC address operates at the data link layer of the OSI model and is essential for the functioning of Ethernet and Wi-Fi networks.

When a device communicates over a local network, it uses its MAC address to send and receive data packets. This addressing ensures that the data reaches the correct destination device without confusion or interference from other devices on the same network.

In contrast, public and private IP addresses are used for identifying devices on a broader scale, particularly when devices communicate over the internet or across different networks. A public IP address is unique across the entire internet, while a private IP address is used within a local area network (LAN) and is not routable on the internet. A subnet mask, on the other hand, is used in conjunction with IP addresses to define the network and host portions of an IP address but does not identify a device itself.

Thus, the correct option emphasizes the unique and specific role of the MAC address in local networking.