What defines a broadcast transmission?

A broadcast transmission is characterized by its dissemination to all possible recipients on a network rather than targeting specific individuals or devices. This means that when a message is sent using a broadcast method, every device connected to that network can receive and process the message. The essence of broadcasting lies in its reach, as it does not require prior knowledge of which devices are present; it simply sends the message out to anyone that can "listen" on that network segment.

In contrast, the other choices pertain to more targeted communication methods. Sending a message to specific recipients implies direct communication suited for unicast transmissions, whereas a message with a time delay leans towards asynchronous communication rather than the spontaneous nature of broadcasting. Lastly, responding to a direct request indicates a more interactive communication style, which also does not fit the nature of broadcasting. Thus, the definition that aligns with broadcast transmission is the one highlighting its all-encompassing reach to all network participants.