Final answer:
The MAC address is located at the Data link layer of the TCP/IP model, where it serves as a unique identifier for hardware on a local network.
Step-by-step explanation:
The MAC address can be found at the c) Data link layer of the TCP/IP model. The Data link layer is responsible for node-to-node data transfer between two directly connected nodes. It handles the communication between the hardware on the local network and is also where the Ethernet protocol operates. The MAC address, which stands for Media Access Control address, is a unique identifier assigned to a network interface controller (NIC) for use as a network address in communications within a network segment.