Which option correctly describes a MAC address's role?

• A. The hardware address of a network interface
• B. The device's IP address
• C. A domain name
• D. The subnet mask used by the network

Answer: (A)

The MAC address is the hardware identifier assigned to a network interface card and is used to deliver frames on a local network. It operates at the data link layer, so every NIC has a unique MAC that switches and other devices use to ensure a frame reaches the correct machine within the same LAN. IP addresses, in contrast, identify devices for routing across networks; domain names are human-friendly identifiers that resolve to IPs; and a subnet mask defines which portion of an IP address is the network portion to determine local versus remote destinations. So the role described by the hardware-address option is the one that matches how MAC addresses function in practice.