A node is a device, such as a computer or printer, that has a unique address and is attached to a network.

• A. A central server that manages all devices
• B. A software module for security
• C. A device that prints data
• D. A device, such as a computer or printer that has a unique address and is attached to a network

Answer: (D)

A node is any device on a network that can send or receive data and has its own unique address so the network can deliver messages to it. Computers, printers, or other peripherals become nodes whenever they’re connected to the network and assigned an address (such as an IP or MAC address). That exactly matches the description: a device like a computer or printer that has a unique address and is attached to a network. The other options describe a specific role, a non-device software module, or a device without mentioning its network address, so they don’t fit the general idea of what a network node is.