Explanation:

Introduction:
In this question, we are asked to identify which of the given options is not a means of communication. To answer this question, we need to understand the concept of communication and the different means through which it can be achieved.

Means of Communication:
Communication refers to the process of exchanging information, ideas, thoughts, or messages between individuals or groups. It plays a vital role in human interaction and enables us to convey our thoughts and feelings to others. There are various means of communication, including verbal, non-verbal, written, and technological methods.

Analysis of Given Options:
Let's analyze each given option to determine whether it is a means of communication or not:

a) Post Card:
A post card is a type of written communication. It is a piece of cardstock or thick paper that is used for sending messages through postal services. People write their messages on the post card, address it to the recipient, affix a stamp, and send it through the mail. Therefore, a post card is considered a means of communication.

b) Radio:
Radio is a technological means of communication. It uses electromagnetic waves to transmit and receive signals, allowing for the broadcast of information, news, music, and other content. People can tune in to different radio stations to listen to programs and stay updated with the latest happenings. Hence, radio is a valid means of communication.

c) Computer:
A computer is also a technological means of communication. It is widely used for various forms of communication, such as sending emails, instant messaging, video conferencing, and accessing the internet. Computers enable individuals to connect with others across different locations and exchange information efficiently. Therefore, a computer is a means of communication.

d) Cycle:
A cycle, in this context, refers to a bicycle. It is not a means of communication as it is a mode of transportation rather than a method for exchanging information or messages. While riding a bicycle can facilitate physical movement, it does not serve the purpose of communication. Hence, a cycle is not a means of communication.

Conclusion:
Among the given options, the one that is not a means of communication is "d) Cycle." While all the other options, namely post card, radio, and computer, are valid means of communication, a cycle is solely used for transportation and does not facilitate the exchange of information or messages.

A cycle is a mode of transport and not a means of communication. Post cards, radios, and computers are all used for communication purposes.