One of the following is a reason that the Ethernet protocol uses physical addresses: A. It defines a logical address scheme for devices.
B. It uniquely identifies devices at layer 2.
C. It creates a differentiation between layer 2 and layer 3 communications.
D. It allows the node to decide if the device is remote or local.
The correct answer is B. It uniquely identifies devices at layer 2.
Explanation: The Ethernet protocol uses physical addresses, also known as MAC (Media Access Control) addresses, to uniquely identify devices on a local network at layer 2 of the OSI model. This allows devices within the same network to communicate with each other directly, ensuring that data packets reach the correct destination. Each device has a unique MAC address, which helps prevent conflicts and ensures accurate delivery within the local segment of the network.