Which of the following is not a component of a basic communication system?

In a basic communication system, the essential components include a transmitter, receiver, and a medium for transmission. The transmitter is responsible for converting information into signals suitable for transmission, while the receiver converts those signals back into understandable information.

The inclusion of a visual display unit as an option is significant because it's not traditionally seen as a core component of basic communication systems. Basic systems primarily require a transmitter to send information and a receiver to receive it. The visual display unit, while useful for presenting information received, is not necessary for the fundamental operation of communication itself.

On the other hand, both the microphone and other components like the transmitter and receiver play integral roles in the capturing and transmission of audio signals. Therefore, recognizing that a visual display unit is not a foundational component helps to clarify the basic communication system structure.