Correct Option: D. Switch Explanation of Why the Answer is Correct: In a computer network, a workstation (which is typically a personal computer or a terminal used by an end-user) is usually connected to a switch. A switch is a networking device that connects devices within a local area network (LAN). Here’s a step-by-step breakdown of why a switch is the correct answer:

1. Function of a Switch:
2. A switch operates at the data link layer (Layer 2) of the OSI model. Its primary function is to receive incoming data packets from one device and forward them to the correct destination device on the network. This is done using MAC addresses, which are unique identifiers assigned to network interfaces.
3. Direct Connections:
4. Switches allow multiple devices (like workstations, printers, and servers) to connect to the same network. Each device is connected to the switch via its own dedicated port, which helps in reducing collisions and improving overall network performance.
5. Efficiency:
6. Unlike hubs, which broadcast data to all connected devices, switches intelligently send data only to the device that needs it. This makes switches more efficient and faster, especially in networks with many devices.
7. Scalability:
8. Switches can easily be added to a network to accommodate more devices, making them a scalable solution for growing networks.

Why the Other Options are Wrong or Weaker:

• A. Hub:
• A hub is a basic networking device that connects multiple Ethernet devices, making them act as a single network segment. However, it operates at the physical layer (Layer 1) and does not filter data. This means that when a hub receives data, it sends it to all connected devices, which can lead to data collisions and network inefficiency. Hubs are largely outdated and have been replaced by switches in most modern networks.
• B. Modem:
• A modem (modulator-demodulator) is a device that modulates and demodulates signals for data transmission over telephone lines or cable systems. It connects a network to the Internet but does not connect multiple devices within a local network. Therefore, while a workstation may connect to a modem for Internet access, it does not connect directly to it for local networking purposes.
• C. Router:
• A router is a device that connects different networks together, such as a local network to the Internet. It operates at the network layer (Layer 3) of the OSI model and is responsible for directing data packets between networks. While a workstation may connect to a router for Internet access, it typically connects to a switch within the local network for communication with other devices.

Summary of Key Points:

• A workstation is typically connected to a switch in a local area network (LAN).
• Switches operate at the data link layer and efficiently direct data to the correct device using MAC addresses.
• Hubs are outdated and less efficient than switches, as they broadcast data to all devices.
• Modems connect networks to the Internet, while routers connect different networks but do not serve as local device connectors.

This understanding of network devices is crucial for anyone studying computer networking, as it lays the foundation for more advanced topics in network design and management.