Which type of communication rule best describes CSMA/CD?

• A. Flow control
• B. Message encoding
• C. Access method
• D. Message encapsulation

Answer: (C)

CSMA/CD is all about how devices gain access to a shared network medium. It lays out the rules for when a device can start transmitting on the same wire and how to handle collisions if two devices transmit at once. In other words, it’s a method for coordinating access to the channel in a multi-user environment, which is precisely what an access method describes.

Why this fits best: CSMA/CD governs the process of listening before transmitting (Carrier Sense), allowing multiple devices to attempt to send (Multiple Access), and detecting collisions so devices can stop, wait, and retry (Collision Detection). This is fundamentally about sharing the medium efficiently, not about controlling data flow between sender and receiver (flow control), encoding the signal on the wire (message encoding), or wrapping data into frames/packets (encapsulation).

So the rule described by CSMA/CD is an access method, which is why it’s the best answer.