What is a MAC Address?

A MAC address, or Media Access Control address, is indeed a unique identifier assigned to networking devices. This identifier is used at the data link layer of a network to ensure that data packets are delivered to the correct device within a local network. Each MAC address is typically a 48-bit number, represented as a string of hexadecimal digits. It uniquely identifies network interfaces for communications on the physical network segment.

This unique identification allows devices, such as computers, printers, and routers, to communicate with each other effectively, making it crucial for network operations. The permanence of a MAC address means that it normally does not change, unlike IP addresses which can be reassigned or altered based on the network configuration. This foundational role of MAC addresses in local area networks (LANs) highlights why the correct answer is a unique identifier assigned to networking devices.