What kind of address is used by ARP to identify a device on a local network?

ARP, which stands for Address Resolution Protocol, is designed to map an IP address (which operates at Layer 3 of the OSI model) to a MAC address (which operates at Layer 2). This mapping is essential for facilitating communication on a local network, as data packets must be delivered to the correct device on the physical layer.

When a device on a network wants to communicate with another device, it first needs to know the MAC address associated with the target device's IP address. The ARP protocol allows the sending device to broadcast a request to the local network asking, "Who has this IP address?" The device that has the corresponding IP address responds with its MAC address.

This process is crucial for enabling Ethernet frames to carry the necessary data to the appropriate hardware address. As a result, the MAC address is specifically used by ARP to identify devices in a local network environment, making it the correct choice in this context.